Given The Binding of Isaac is a roguelike with many items that change your playstyle, it's not surprising that a few have a reputation for getting skipped by most players due to being unwieldy, too powerful and boring, having undesirable side effects, or simply because they're just that awful. A few items have gotten Rescued from the Scrappy Heap thanks to either balance patches or following expansions, thankfully.
Note that any Scrappy Weapon may also be rescued from being such if one manages to find a weapon which it can synergize with.
NOTE: Because of the enormous amount of content as of the Repentance expansion, all spoilers are unmarked. You Have Been Warned.
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Explosive items
Generally speaking, most passive items that cause explosions that you can't control are looked down upon by the community, as their blast radius can easily damage you. As such, picking up Host Hat or Pyromaniac to No-Sell the explosions from these items is recommended.
- Bob's Brain and BBF. The former is an explosive projectile familiar that you can fire at enemies for poison damage. The latter is a friendly Boom Fly that bounces across the room, exploding on contact with an enemy. What makes them divisive is that they have a tendency to respawn as you're firing your tears in close-quarters; there's nothing worse than having them respawn and explode on top of an adjacent enemy, catching you in the blast. While BBF deals contact damage to enemies upon entering a room, it will explode not too long after. Both items also synergize with most bomb modifiers, including Mr. Mega! Bob's Brain, at least, was toned down a bit in Afterbirth, as it now can't be fired for a few seconds after it spawns or after you enter a room, preventing surprise explosions. Then Repentance came along and gave both items the ability to "synergize" with Bomber Boy, which substantially increases their blast radius, and thus their ability to hurt you.
- Lil Delirium from Afterbirth† will transform into a copy of a different familiar every ten seconds, inheriting their properties and attack style. Unfortunately, the list of familiars it can copy includes both Bob's Brain and BBF, which retain all of the problems mentioned previously (and in the case of Bob's Brain, work much like before Afterbirth), and as such it's considered as much of a liability as they are.
- Fire Mind allows you to shoot tears that inflict burn Damage Over Time to enemies… but each tear has a chance to explode on contact with an enemy, with said explosion having a generous blast radius but dealing pitiful damage to enemies. Worse is that the chance for explosions scales with your Luck stat, so the more luck you have, the more explosions you create. It completely ruins your primary attack's use for close-quarters combat, only allowing for Hit-and-Run Tactics; and even then, there are some enemies like Globins that love to be in your face, making avoiding damage during hit-and-run tactics very hard. Picking up certain tear modifiers, however, eliminates the explosion chance while retaining the burn damage over time, like Brimstone, Mom's Knife, or Technology. It is also a non-issue for Tainted Lilith in Repentance, since her tears are fired from a distance via Gello.
- Ipecac is less of an example as the others in this folder, but still earns its place nonetheless. While Fire Mind only needs to touch an enemy to explode and depends on the Luck stat in order to do so, Ipecac explodes all the time and doesn't need to touch an enemy to do so. The projectile launched by Ipecac can touch a wall or rock and explode on impact, making it easy to blast yourself in the face by accident because of this. Mastered, however, the item is considered a "hard-carry item" due to the explosion size and the intense damage it can deal, as well as the fact possessing it means you no longer need bombs to destroy obstacles or open Secret Rooms.
- 3 Dollar Bill, Fruit Cake, and Playdough Cookie have also won quite the amount of detractors as well because of their tendency to proc explosive effects that one wouldn't like to find — all three can roll Fire Mind, while Fruit Cake can also roll Ipecac. It is entirely possible for a run to end by picking up any of these items and having them roll an explosive tear effect at the worst possible time.
- Curse of the Tower spawns Troll Bombs randomly around the room each time you take damage, with each bomb taking in the additional bomb effects you might have picked up in the run. This item activating usually results in the player being blown up and taking even more damage, especially in half-size rooms or if they're unlucky enough to also have an item like Mr. Mega, Bomber Boy or Scatter Bombs. It also makes Devil Beggars and Blood Donation Machines virtually unusable, as they tend to get blown up immediately after one use. Fortunately, as of a late update in Afterbirth, getting hit by the bombs this item produces does not create more bombs, preventing a Cycle of Hurting. Host Hat or Pyromaniac can also turn Curse of the Tower into a screen-clearing Smart Bomb.
- 7 Seals has its issue where its randomness and the effects of each of the little Harbingers can make it somewhat unreliable, but one of the item's main problems is the War transformation. The locustsnote he spawns (red locusts) are highly damaging, but can be easily turned against you due to the fact they have the same blast radius and damage as a bomb. Simply put, much like BBF, the red locusts can damage you whenever you enter a room whether you want it or not, making it a prime reason why this item is looked down on. And if the game is feeling spiteful, War may be the most common Harbinger 7 Seals will roll, causing red locusts to spawn over and over. Of course, everything that applies to this item also applies to the Locust of War trinket. Thankfully, Repentance removed these two from this category by making the blast radius of red locusts much smaller, which while making them less effective at crowd control, it's a small price to pay when it means they're no longer blowing up in your face all the time.
- IBS, similar to Tainted ???'s gameplay gimmick, has a chance to give you one of several throwable poops or otherwise poop-themed effects whenever you damage an enemy. Unlike Tainted ???, you can't control when to use these poops — they activate on their own, indicated by Isaac's sprite flashing red, and deploy automatically once you stop firing. This is bad enough on its own, since you can't shoot when you're holding a poop, but it can also give you an active throwable bomb or the effects of an Explosive Diarrhea pill at complete random. Even green poops, ordinarily one of the more useful kinds due to the poison clouds they emit, can be a liability. If the RNG decides to give you fire poop while you're standing near them (or one of their gas clouds)… BOOM!
Original (including Halloween Update and Wrath of the Lamb)
- My Reflection is a particularly infamous one, as it just makes your tears boomerang around wildly, cutting your range and making it hard to aim. Some combinations using it will screw you even harder, such as combining it with Ipecac or Bob's Rotten Head, causing your explosive projectiles to boomerang right back at you. Even worse is that the Suicide King challenge in Rebirth sticks you with the My Reflection + Ipecac combo for the entire run. The item did receive in update 1.7.9 an (admittedly significant) improvement on damage at the cost of a luck nerf, but while this may make it appetizing as an early pick, the item's core problems and amount of negative interactions it has with most of the other items in the game still prevent it from being a remotely good pick. It works surprisingly well with Azazel, however, as it's one of the few items that increases his otherwise short range.
- Kamikaze! is another infamous example: at the cost of half a heart, you explode and deal 40 damage to enemies around you, and the item has infinite uses. When you compare the damage with traditional bombs (which deal 60 damage) and combine it with the self-damage, it's no surprise why everyone doesn't want to even see this item in Treasure rooms, even with explosion immunity from Host Hat or Pyromaniac on tow. That it's the point of a certain challenge in Afterbirth doesn't help at all. Repentance did buff the explosion damage to a massive 165 (which is higher than that of a regular bomb, which were also buffed to deal 100 damage) and increased its blast radius to that of a Mr. Mega bomb, but unless you have high health or explosion immunity, there are still far better alternatives. Plus, for some reason Kamikaze is not treated as self-damage like Razor Blade and Blood Rights are, meaning that using it can lower Devil/Angel chance, destroy Perfection, or cause Damocles to fall.
- The Bible is a 6-room charge activated item that grants flight and… that's it. Having flight is a big advantage, as it increases overall mobility and allows for obtaining pickups that you would otherwise have no access to. But an item that grants such effect each 6 rooms, when there's already a bevy of items that do it permanently, is quite lackluster. On the other hand, the item instantly kills Mom and Mom's Heart/It Lives, but be careful not to use it on Satan (or in Wrath of the Lamb only, Isaac or Blue Baby), as it'll kill you instead. Repentance made it a bit less situational by buffing its charge time from 6 to 4 rooms.
- The Necronomicon isn't disliked so much as it is just ignored due to there being many more alternatives available. It's a 6-room charge item that deals 40 damage to every single enemy in the room, meaning it can kill tender enemies and heavily soften the tankier ones, so it's a Death tarot card on command and can save a lot of time in dealing with hordes of enemies, especially early-game. Similarly to The Bible, however, its 6-room charge makes it pretty underwhelming. Even a cheaper alternative from Rebirth is Blank Card + Death, which takes 4 rooms to charge. Repentance gave the item some love, though, as not only was its charge time reduced from 6 to 4 rooms (much like The Bible), but it now synergizes with both the newly buffed Missing Page trinket and the Missing Page 2 passive item, since both now add an additional Necronomicon effect that stacks with each other for up to 120 damage, which easily decimates everything in the room, but even then, due to RNG, you will probably not find all three of those items in a single run; The Necronomicon is an active item, which hogs your active item slot, the Missing Page is a trinket that takes up your trinket slot unless you gulp/smelt it, and the Missing Page 2, while a passive item, is incredibly underwhelming by itself.
- On the other side of the spectrum is Mom's Knife, one of the biggest Game Breakers, but also considered by a few people to be one of the dullest items in the game. The knife you can throw is extremely powerful at its longest range, dealing enough damage to do a number on even Final Bosses, especially if they're stationary (like Mega Satan). However, the knife is infamous for either not synergizing well with other tear effects, or at all, which tends to kill any powerful build you may have. As a result, some players (including seasoned veterans) often opt to skip this item, either due to its anti-synergistic potential, or in an attempt to make the difficulty of the game truly shine. Even those that will take Mom's Knife can find the item unwieldy at times, such as trying to fire diagonally but instead doing so horizontally/vertically due to the input being frame perfect. Repentance worked around this issue by making the input no longer require to be frame perfect.
- Bum Friend is a familiar that picks up money and can grant other pickups, including health, bombs, keys, trinkets and consumables. The problem stems from the fact the pickups are always chosen at random, so it can give you a pickup that you weren't intending to get. This can also potentially screw you from buying an item from shops that could be of help in the run. People thus consider buying said pickups and items at shops much more reliable, since at least you can guarantee you'll get what you're looking for. It does at least become better if you have more money on you or are in floors like The Womb onward, floors which don't usually have shops. Update 1.7.9 did grant it a useful buff by allowing it to now spawn batteries or, rarely, items from the Beggar Item Pool (which includes some shop items like navigation ones, health upgrades and Bumbo), making it a better pick if you don't mind forfeiting the money.
- Technology 2 is another very infamous example. Having a constant laser that fires while you do is a nice idea for an item, but the main problem is that it halves down your firing rate and, on top of it, cuts down your damage stat directly as well, and significantly so. The laser itself, much like Technology, has no knockback, which when combined with the massive damage reduction and the reduced rate of fire means you'll need to shoot down the enemy with the laser and the tear to make the damage count. Rebirth further emphasized its problems by making the laser itself deal even less damage, causing tanky enemies to take AGES to go down unless your damage stat is good. Finally, when used by Cain (or alongside items that make you fire tears only from the right eye, like Lead Pencil from Afterbirth†), tears won't fire at all anymore, only firing the laser that deals pitiful damage. As a result, compared to the more traditional Technology, Tech 2 is widely considered to be a huge downgrade. It doesn't help Rebirth introduced Tech.5, a laser that has a random rate of fire but doesn't replace your main source of fire nor affect your stats, and has its own effects, which pushed Technology 2 even further downhill. Fortunately, Repentance removed it from this category by making it no longer reduce your Damage stat, making the rate of fire downgrade much lower, granting the beam slight knockback (much like with other Tech items), and granting the regular Technology effect when used by Cain/with items that fire from the right eye, meaning that it's now much more worth a try.
- Another powerful item that isn't well-liked is Epic Fetus. The air strikes you summon are very powerful, but take some time to come down onto enemies to deal damage — by that point, enemies might as well be in your face, meaning that it can sometimes become very difficult to not take damage in some rooms. The best way to make use of the item is also by attacking groups of cluttered enemies, which won't always be a thing unless they happen to group themselves to chase you. Due to this, despite the excellent damage you're able to deal with the item, it is considered to be unwieldy by some.
- Holy Water is a familiar that activates when taking damage, but compared to other similar familiars, it breaks and merely spawns a small puddle of blue creep that deals some damage to enemies, similarly to the Lemon Mishap effect. Since enemies are still able to move around when they stand on the creep, the damage they'll take is scratch damage at best, especially during later chapters where enemies are tankier and faster (and from the Womb onward, you take a full heart of damage each time). Oh, and it can only be used once per room. This makes not only for a widely disliked item, but alongside some items like Breath of Life or Trisagion, it is one of the go-to examples when arguing about why the Devil Room item pool is better than the Angel Room item pool, even with the existence of other powerful items like Sacred Heart or Godhead. Repentance fortunately threw Holy Water a bone and heavily reworked it by making it a familiar that flies forward when Isaac shoots (similarly to Bob's Brain) and breaks on contact with enemies, while the creep petrifies enemies and bosses to make them take the full brunt of the damage; as a result, it's now considered one of the best non-stat boosting Angel Room items, firmly removing it from this category.
Rebirth
- Dr. Fetus, of all items, became this in Rebirth. A Difficult, but Awesome tear modifier that can damage you if you're not careful, in the original game it was still seen as a borderline Game-Breaker due to its tremendous damage output. In Rebirth, however, Dr. Fetus bombs had the self-damage reduced and damage output massively reduced, meaning that it now fails to consistently One-Hit Kill many normal enemies and kills bosses very slowly. It did receive an increased fire rate, which theoretically makes Dr. Fetus an overall damage upgrade, but since bombs have a tendency to knock each other around — often into your face — it's still not worth picking it up. By comparison, fellow explosive attack Ipecac has the same self-damage, but deals much more damage to enemies. Fortunately, Afterbirth restored Dr. Fetus to its former glory, as well as adding tons of new synergies with that, and Repentance further buffed the item by making explosions inflict no knockback to other bomb shots.
- Cursed Eye; while the quadruple charge shot is nice, if you are hit while charging the shot (but not while holding a full charge), you will be teleported to a random room. This makes fighting the more difficult bosses even more problematic, as even one mistake can warp you away and ruin all of your progress. Fortunately, this drawback can be worked around by picking up the Black Candle item (which eliminates the teleporting effect and leaves you with the quad shot) or a different tear modifier (like Brimstone). The teleporting effect can even be beneficial in some circumstances — most notably, allowing you to take a free item from the Boss Rush room. Repentance also buffed the item by making the full charge become a quintuple shot, and added a few more synergies with the item, such as with Technology. On the other hand though, woe unto you if you're playing as Tainted Eden and you reroll into Cursed Eye without realizing it and get teleported out of one of the Marathon Bosses such as Hush or Delirium.
- The Stop Watch, which is frowned upon for either being too powerful or too weak of an item, depending on the game's version. In Rebirth, it is a huge Game-Breaker which increases your speed stat and slows down enemies and projectiles for the entire game, which makes it become a complete cakewalk. In Afterbirth, however, the item is this instead, as its slowdown effect not only lasts for only one room, but only activates if you take damage (though this can be worked around by using the Holy Mantle). Repentance restored it to its former glory by applying its slowdown effects to the entire run again, but much less powerfully than before, though with the caveat of synegizing with the actual slow status effect.
- Tiny Planet is another particularly infamous one. Sure, it's a stat upgrade and has some interesting synergies, but the orbiting tears on their own cover much less range in front of you than firing them straight and are nigh-impossible to aim, meaning that players tend to avoid it. It doesn't help that the effect combines badly with certain strong items, such as Dr. Fetus and, before Repentance, Mom's Knife. Only a few items gain a net positive with this one, including Brimstone and Technology.
- Missing No. is another highly infamous example. The item will reroll all of your items like the D4 and modify your stats, but that's not the bad part… that would be that, whether you want it or not, this will happen again at the start of each floor. This can turn any build you may have (be it a decent one or even a Game-Breaker) prior to picking Missing No. up into a Luck-Based Mission in which you'll hope the items granted to you don't make you underpowered or even worse, cause the run to be borderline unplayable. The item is also one of the few unable to be rerolled by an another reroll effect, so you'll have to deal with holding onto it. It is technically able to turn any bad run you may have into something much better, but then it'll just take that run away on the next floor. You're better off with the D4 or D100 to get controlled versions of these effects. Unlike many other items on this page, Repentance only made the item even worse due to the nerfs made to reroll effects, as while any items that are removed can be encountered again during the run, any transformations from items that grant them and any red heart containers you had from health upgrades will now be removed if you lose the items that granted them.
- Isaac's Heart trumps all of the examples above, being a risk-reward item that's far too light on reward. Your body no longer has a hurtbox, which sounds great… if it wasn't for the fact said hurtbox will now be following your back as a familiar that enemies will be 100% of the time aiming for. Knowing how the mechanics for familiars work (and as later infamously seen with characters like Lilith's Incubus), having a hitbox that trails behind you is not a good thing at all. It's especially terrible when it's not the first familiar on your line, as it makes the heart much harder to properly protect. It's because of these traits that players will almost always avoid it. Keyword being "almost" because, in spite of its negatives, the item does have a few situational positives that can lead to some Game Breaking combos that make infinite use of red heart containers, such as Blood Donation Machines or the IV Bag for infinite money, offering to to Demon Beggars until they pay out with an item, using the Razor Blade for infinite damage stacking, or using Blood Rights to damage everything in the room until it's empty of enemies. The heart familiar can also fortunately be sacrificed with the Sacrificial Altar in Afterbirth† for a free item in return, and from the Devil Room item pool at that. Still, without a way to exploit Isaac's Heart to your benefit, do not ever think about touching that item pedestal containing the item.
- Repentance brought a mix of buffs and nerfs to the item. The great? The heart will actively position itself opposite of where you shoot, it now has a Charged Attack where it will stomp the floor to push enemies and bullets aside and release a ring of shots to protect itself, most enemies now track your body instead of the heart, and your body will also deal contact damage to enemies. The egregious? Red heart containers are now depleted despite the body invincibility, removing every single game break with this item. And Sacrificial Altar will also no longer sacrifice the heart. All of this, while it makes it easier to protect the heart, now gives the item no incentive to be picked up ever, pronouncing its status as exactly what it is: a joke.
- Whereas many of the "Bean" items are purposely bad, but accepted due to balance purposes, the same can't be said about the Butter Bean. It's an active item that only has the effect of producing a small fart that can knock back some enemies. At least it recharges spontaneously, and in Afterbirth it can deflect bullets. Still, considering that all this item does is a miserable fart, you'll still want to swap Butter Bean with another much better active item. Afterbirth† made it so swapping it with another active item repeatedly can transform it into "Wait What?", an identical-looking bean that loses the fast recharge time in exchange for creating a circle of rock waves around Isaac; however, for whatever reason, the swapping effect was removed in Repentance, in exchange for making Butter Bean's fart knockback deal damage to enemies if they collide with obstacles, walls or other enemies, an effect that doesn't compensate for its issues.
- Breath of Life was one of the go-to examples when arguing about why the Devil Room item pool far eclipses the Angel Room's own. It's an active item that is used by holding the activate button, depleting the charge bar to zero to give you a second of invincibility. However, the item has several downsides: first, if the button is left pressed for too long while you're invincible, you'll start to take damage instead of negating it. Second, after usage regardless of whether it was successful or not, the charge bar must hit max charge for the item to be used again. Its invincibility period has its uses, but they're extremely situational and invincibility periods are better done by other items anyways, like Book of Shadows or The Gamekid. Not to mention, the fact Breath of Life is found by skipping in a Devil Deal and hoping for the next room to be an Angel Room that could potentially reward more, only to find this item instead of a more useful one, is extremely disappointing.
- Repentance gave the item a buff that allows it to be used in combat, by creating Bolts of Divine Retribution (similarly to Crack The Sky or Holy Light) on contact with an enemy, but this buff didn't do anything to improve on its core problems. It wasn't until the 1.7.9 update when the item got reworked by drastically reducing the time it takes for the invincibility to kick in, giving a visual cue when it's active, and granting it further offensive and defensive usage by summoning a cross of powerful holy beams and a shield on contact with enemies as the invincibility activates, turning what was once one of the most underwhelming items into a Difficult, but Awesome item.
- Soy Milk is in roughly the same boat as Tiny Planet. At the cost of reducing your tear size and slashing 80% of your damage, it massively boosts your fire rate, to the point that a starting Isaac with Soy Milk can shoot 30 tears per second. Unfortunately, the game has a hardcoded limit of 15 tears per second, meaning that while it's technically a bit more DPS than your default tears, that's only if you make every shot count. Given the tears' knockback, the game's enemies and their erratic movement patterns, making all your tiny tears hit their mark so the damage output is at least decent is a huge pain in the neck — the DPS is so poor, all bosses become Marathon Bosses, and even flies take a lot more shots before they're down. And to add insult to injury, it's a special item in Rebirth, so once you see it, your chances of a really good item in your current run fall dramatically! Only once you gain a lot of Damage ups or synergize Soy Milk with other certain items does it become a Game-Breaker, due to its high firing rate carrying over. Fortunately, in Afterbirth, Soy Milk is no longer a special item, meaning that it no longer interferes with your ability to get really good items just by showing up. As of Repentance, the tears' knockback was also reduced dramatically (allowing tears to hit their target more frequently), the tear cap is no longer hardcoded at 15 per second, items that increase the tears stat affect Soy Milk's fire rate (which combines well with the previous change), a good number of items gained synergies with it, and there's finally the possibility of getting Rock Bottom alongside it, which prevents the damage reduction while keeping the increased rate of fire.
- Monstro's Lung replaces Isaac's tears with a charged shot that spews a cluster of 14 tears that fly out at varying distances, similar to Monstro's main attack. Similarly to other charged tear modifiers like Brimstone and Tech X, this makes you more vulnerable to fast-moving enemies or enemies that get up in your face, as there is no reliable way to push them back while charging. Where Monstro's Lung really falls flat though is the trade-off compared to other charged attacks — each tear only deals base damage, meaning that the spew's innacuracy makes it only effective when very close to enemies or facing particularly clustered groups. It also doesn't come with piercing to offset the downtime charging causes. The item does have a ton of cool and useful synergies, and it can see great effect with damage/fire rate upgrades, but without them, it's a risky pickup in the early game by itself in most cases.
- The D10, at a 1 room charge, allows you to reroll… the enemies in the room. While this can be somewhat useful in removing Demonic Spiders, there's also the very likely possibility of it rerolling them into something even worse. Repentance at first attempted to fix this by making it so they reroll into enemies that have a similar amount of HP, but in reality it made it worse by removing a lot of what it had going for it. Miraculously, update 1.7.9 gave the item a much needed rework, now instead downgrading enemies on use by turning them into different, weaker versions of them (say, transforming a Trite into a Hopper) at the cost of now requiring 2 rooms to charge, which has removed it from this category by many people.
Afterbirth
- The Glass Cannon, on release, used to reduce your health to half a red heart, but gave you an on-command massive tear with scaling (but always high) damage. However, following the November 4th, 2015 update, it instead reduced you to half a heart — including soul hearts and black hearts — turning you into, appropriately enough… a Glass Cannon. To say that people are not amused is a massive understatement. However, it becomes one of the most useful items in the hands of The Lost, who has no health. Repentance took it from this category for some after it was made so that it no longer depletes your health to half a heart, instead only significantly increasing damage taken in that room and temporarily causing it to break if you're hit while carrying it; while still very risky, it's a massive improvement over its original effect.
- The Wiz doubles your rate of fire at the cost of sticking you with the "R U A Wizard" pill effect for the rest of the run, forcing you to shoot diagonally. Given that the game is based around being able to shoot in the cardinal directions, meaning that "R U A Wizard" is generally considered a negative effect, it's not a popular item at all. A few items can work around it though, most notably Tractor Beam and Technology 2, but considering the Random Number God, good luck getting these specific combos to begin with.
- Betrayal and My Shadow are, compared to the rest of Devil Room item pool, horribly outclassed. Upon hit, enemies become charmed and attack each other rather than you, or are inflicted fear and you summon flunkies that deal damage to them but are destroyed easily, respectively. Not only are the effects incredibly lackluster, but since they activate by taking damage, you're better off with rerolling them or picking up any other item you may find in the room. Both items got buffed quite intensely in update 1.7.9 of Repentance by reworking them to no longer be on-hit effects, but rather having unique effects to each othernote , removing them for some from this status.
- Spear of Destiny was seemingly introduced as the Angel Room equivalent to Mom's Knife in the Devil Room (both items working like swords), but in practice it's extremely lackluster. Both items deal twice your damage on contact, but Mom's Knife deals damage up to 20 times per second, whereas the Spear of Destiny hits… only 3 times per second. While the hitbox for the spear is bigger, the fact that Mom's Knife deals damage drastically faster makes it a much safer choice at the end of the day. A few active items that grant invincibility, such as Unicorn Stump or The Gamekid, can work around the issue and make for a usable way to deal melee damage, but again, the fact Mom's Knife can do the very same does not help its case. As of Repentance, the existence of an actual sword item in Spirit Sword only makes Spear of Destiny even more redundant.
- Mega Blast sits in a similar boat to Mom's Knife in that it's an overpowered item that is disliked for being overpowered, except it takes the concept of "overpowered" up to eleven. Not only is Mega Blast a cheap item in the Devil Room (at a cost of only one heart container, compared to other Game Breakers like Brimstone or Mom's Knife which cost two containers), the gigantic laser you shoot lasts for 15 seconds, enough time to vanquish even Damage Sponge Final Bosses like Hush, Mother, or even Delirium. The unlock requirements are why it is Purposely Overpowered to begin with (defeating Mega Satan as all and every character), but the fact this item alone makes every room in the game and every boss in the game a complete joke is what removes much of its charm for many. And again, like Mom's Knife, Mega Blast had a flaw pre-Repentance that made it unwieldy for many people, in while its charge time of 12 rooms before it can be used again counterbalances its strength, it also requires 3 batteries to fully charge instead of one (unlike its Angel Room counterpart Delirious), heavily cutting on its usability; Repentance made this issue less prominent by reducing the number of batteries to 2.
- Afterbirth added a bunch of new transformations; of these, Conjoined stands out for being extremely divisive. After picking up three shooting familiars, Isaac grows two faces on his cheeks that fire tears along side him, at the cost of directly reducing his damage and tears, an effect no other items or transformations have; while the transformation is technically a significant increase in DPS, the stat downs it grants, despite being low enough to compensate on their own, tend to lower your overall DPS in front of you, which isn't desirable without enough damage/tears upgrades. The spread at which the tears fire is much wider than that of The Inner Eye, firing at 90° ala The Wiz (described above), so while it has the potential for better crowd control and some powerful synergies, it's not as effective against enemies right in front of you (not helped by the aforementioned stat reductions); this problem is more apparent on tight spaces. Though the transformation is rare (pre-Repentance, only seven familiars counted towards progress for the transformation), the familiars that compose it are some of the most underwhelming in the gamenote , so chances are, if you have a bunch of familiars, you're losing on some of the stronger items, which is quite problematic in the early game (though not so much in the late game). Repentance did make Conjoined easier to obtain by including a drastically higher amount of familiars that contribute to progress, many of which are much strongernote , which combined with the higher item count and the various changes to item pools, makes getting the transformation easier; though the stronger familiars that grant the transformation potentially help in playing to its strengths, it still doesn't compensate for its other inherent problems. All in all, it's still a hot topic of debate to this day to whether Conjoined is worth looking for or not; some people argue that its crowd control, increase in DPS and synergy potential far outweigh the front DPS reduction, while others either couldn't care less for the extra shots or consider them a hindrance, while stating that the stat downs it grants are just a potential gut punch to a bad run.
Afterbirth†
- Dark Prince's Crown suffers from being extremely specific on the requirements needed to activate its effects. It grants a sizeable tears up, as well as a range and shot speed up if you're at one red heart… and exactly one red heart, since you'll lose the effect at either half a red heart or with no heart containers; this also means the item has no effect on characters that can't gain red hearts, such as Blue Baby or The Lost; the only character it tends to synergize well with is Eve (since her own Whore of Babylon effect activates at one red heart or less instead of half a red heart).. A bunch of other items already activate their effects at lower red heart requirements, such as The Polaroid/Negative, Whore of Babylon, Empty Vessel, etc., meaning that Dark Prince's Crown competes directly with these items, and can potentially prevent you from unlocking their more powerful effects, despite the noticeable increase in fire rate. If you can't manage to find soul/black hearts to offset the specific red heart requirement, you're left with a highly disappointing item you won't get proper use of.
- Glyph of Balance has a neat concept on paper, but fails to consistently make use of it because of issues regarding its design. The item modifies the pickups dropped by champion enemies to provide you with whatever pickup the game deems you need (more on its complicated criteria can be read on that game's wiki
). The problem lies on how it triggers, which is by killing champion enemies. On Normal mode, champions are guaranteed to drop a pickup, but they are rare compared to regular enemies. However, on Hard mode, Champions are more common but only have a 1/3 chance to drop anything at all. This oxymoron causes the item to become surprisingly situational and, in some cases, completely useless, since you'll rarely be receiving drops from champions either way. Repentance, however, brought a major buff to the item by making it now modify room drops, which are commonplace compared to champion drops, and as a result the item has become significantly more appetizing and a catalyst in soul heart generation, especially in a game where such strategies got nerfed to the ground. - Plan C kills every enemy and boss in the game in a single hit… and then three seconds later, it kills you, too. It's a Smart Bomb with barely any of the "smart" factor in it, as it absolutely requires you to have an extra life in order to make the most use out of it. Its extreme damage output is also offset by bosses with multiple phases to their fights, meaning bosses like Hush or Mega Satan will not survive the first hit but will be ready for Round 2 while you simply die; thus, using the item in their second phase is the next best thing. Furthermore, using it on Delirium will cause you to die first because of its death animation taking so long to finish. It doesn't help that, while it's only likely to appear 1 time out of 5 in an item pool, it can be found in a total of 6 item pools in the gamenote , making it surprisingly more common than one would imagine despite its lowered item weight.
- The Dataminer invokes this without much fanfare, due to being an item put in the game as merely a jab at the Content Leakers that infamously datamined Rebirth. It's a 4-room charge item that merely flips enemy sprites and grants random tear effects, while increasing one of Isaac's stats and decreasing another. Not only are its effects egregious, they are also reliant on the Random Number God and fighting enemies becomes wonky. Oh, and it distorts the level's music, too.
- The Crooked Penny is another 4-room charge that works like a multiple-use Diplopia… but has a catch. The item's description, "50/50", is Exactly What It Says on the Tin: it either duplicates items (granting free copies of those that need to be bought) 50% of the time, or it fails to do so 50% of the time and instead removes every collectible in the room and spawns a measly penny. Half of the time you'll be happy and with your hands full, while the other half you'll be empty handed and cursing the Random Number God for not allowing you to duplicate a Game-Breaker like Brimstone. And knowing the game's AI tendency to troll the player into oblivion… yeah. Overall, this amounts to one of the most divisive items in the entire game, with just as many people willing to passionately defend the item as there are those that loathe it.
- The D Infinity is a dice item that, upon usage, invokes a random dice effect from every other dice item in the gamenote . While not reviled, its randomness and risk of getting an effect you weren't asking for are very much what make it a forgettable or undesirable item by many, and you'll see many other players opting instead for using any other separate dice effect due to their consistency. Fortunately, Repentance removed it from this category altogether by reworking the item, allowing it to instead manually cycle between any of the dice items in the game (including the new Eternal D6 but not including the new Spindown Dice) instead of invoking a random effect, and as a result, it is now widely considered to be one of the most powerful items in the game.
- Bomb upgrades already tend to be hit or miss, but Fast Bombs is one of the most disappointing. It removes the cooldown on bomb placement and grant 7 bombs. Though certainly a fun concept, this effect is incredibly niche, making the extra bombs often more useful than the actual item (which, while two more than most bomb upgrades, is still less than Boom!'s +10). The only real use is the combination with Remote Detonator, which will allow you to quickly one-shot most bosses if you're willing to expend a bunch of bombs, but even that is merely faster than placing all the bombs manually. Repentance gave the item a much-needed buff, making bombs immune to each other's knockback, making the item drastically safer and less prone to launching bombs your way; it's still fairly underwhelming, though.
- Lacryphagy is another highly divisive item as well. Tears will quickly decelerate and become capable of absorbing other tears, causing them to grow until they burst into tears. While the main tear also deals the combined damage of each tear that fed it, the burst tears only deal half damage. The item forces you to pay attention to not just the enemies in the current room, but also to how large the tear has become before it bursts. The item also has a tendency to not synergize well with other tear modifiers. It's likely because of this that Repentance gave the item's synergy potential a massive buff, as items like Brimstone or Technology now synergize with it.
- Trisagion looks a lot like the equivalent to a "holy Brimstone" shot, but in reality has a lot to live up to. The light blasts you shoot pierce enemies but deal only 1/3 of your current damage per tick, and much like Technology, cause no knockback. With a high shot speed stat (a stat liked for its ability to reach enemies faster), each blast becomes even weaker, as they'll go through the enemy faster and thus the damage per tick is less constant; by contrast, a low shot speed stat (a Violation of Common Sense) makes each blast deal more damage, but the problem is that the items that reduce shot speed (like Lost Contact, Godhead, or Sacred Heart) are rare compared to those that increase it, so it's often not worth picking it up. And to rub more salt in the wound, it has a massive tendency to make the game lag like crazy. It's no surprise why the item gets the nickname of "Tri-BAD-ion" by some players. Repentance, fortunately, buffed Trisagion through the introduction of shot speed pills (allowing "Shot Speed Down" pills to "synergize" with the item), plus each blast now causes slight knockback, and the item now has a slew of synergies to go with it… including a "Scrappy Synergy" with Ipecac where the Ipecac-powered Trisagion blasts exploded immediately after you fired them, resulting in you taking unavoidable self-damage whenever you fired (and eventually finding yourself seeing Isaac's last will). Thankfully, the November 2021 update fixed the combo, and Trisagion has been less divisive since then.
Repentance
Although this game brought several balance changes (many of which were already mentioned above) and also introduced some pretty powerful items, some of them have gotten a notable slew of infamy.
- Damocles is one of the riskiest items in the game: on use it spawns a sword above you and causes all natural item pedestals to spawn a free second item beside them (not including items for sale or in chests); the catch is that upon taking damage from an enemy, the sword gains a chance to fall and insta-kill you at any moment without warning. This creates a Sadistic Choice — do you use the sword and try to play perfect from that moment on, or do you pass up on it and miss out on the free items? For most players it's the latter choice, given that it's extremely difficult to do a No-Damage Run and the upside is meaningless when you could lose your winning streak at total random. Extra lives can circumvent the insta-kill to a degree, although the item's positive effect will also disappear once the sword falls. At least Damocles is one of the absolute best items for The Lost and Tainted Lost, since they usually can't take damage anyway, and for Lazarus who gets an extra life per floor, should he die.
- Planetariums have been received well due to the slew of items with good to excellent effects (such as Mercurius, Terra, Uranus, and Neptunus), but a few of them have a lackluster reputation.
- Venus gives Isaac a red heart container and an aura that charms nearby enemies. The aura has a small radius, which unfortunately makes the item mostly restricted to melee enemies. It's certainly not bad, but it does feel like a repeat of other items that inflict similar status effects like Bozo, and it's barely an upgrade over 2Spookynote . Considering you have to skip multiple Treasure Rooms to get a Planetarium, it really stings to get a fairly minor benefit out of it.
- Mars is also not bad, but it certainly feels unwieldy at times. Its effect is certainly excellent: by pressing a movement button twice, it grants you a dash attack that makes you invincible for its duration and deals great damage by itself; it makes Curse Rooms free of entry and also stacks with other items that deal contact damage (like the newly buffed Aries) while synergizing with others (like Kamikaze! and A Pony/White Pony). However, the way it activates has caused a problem too many by activating it when one doesn't want to, which when combined with nearby sources of damage can lead to accidental self-damage and, in the worst of cases, an accidental death through little fault of your own. This becomes a bigger problem if your computer starts to lag, as the activation window for Mars becomes much wider due to the slowdown. And the biggest problem of all is that Mars does not give any additional invincibility frames after the dash attack finishes, which leads directly into the problems stated above.
- When you think of Jupiter, the first thing you'll think of is the Roman god of Thunder and the gas giant of a planet in the Solar System… but not of a "gas giant" in the literal sense. The item is a sizeable speed downgrade that forces you to stay still to build speed and, as soon as you walk, release it in a burst of farts. Not only is its effect mediocre at best, it forces you to play the game differently without offering much reward in return and, to boot, you're going to constantly hear the sounds of farts and the item comes with one of the ugliest costumes in the game. It does provide immunity to all forms of Poison gas damage, but that is not even hinted in the game at all. At least, the item does become more useful by picking up speed upgrades; otherwise, compared to most several of the new Planetarium items (even Venus and Mars), Jupiter has quickly managed to get on people's nerves.
- The Birthright was formerly this. It's a shop item that provides a unique effect tailored to the character you're playing as. Most of these effects are incredibly useful, typically patching up a key weakness or improving on the character's strengths. The problem is that, formerly, only about half of the characters in the game had an effect implemented, and while the item could still spawn for said characters, picking it up did nothing! For players who did not know the effects, it was pretty much a complete toss-up as to whether it was a godsend or a waste of 15 coins, while to those who did know, it felt like a waste of a trip to the shop when it showed up. As of the November 2021 update, however, every single character now has an effect attributed to them and most of them are incredibly useful.
- …except for Tainted Jacob. From the same update onward, picking Birthright up will cause Dark Esau to spawn another clone of himself that will also charge at you. Despite the significant buffs Tainted Jacob received in the same update, if you thought juggling an angry soul trying to kill you was enough, now try juggling two! On the other hand, if you decide to face the risks and play to the item's strengths, both souls charging at you can make facing hordes of enemies or certain bosses easier, since their huge contact damage that ignores boss armor is doubled.
- Thanks to an oversight in the launch version, the Yuck Heart held the dubious honor of being the only item in the Tainted Lost's "better items" pool to be completely useless for him, as a healing item on a One-Hit-Point Wonder. Thankfully, this was fixed in the November 2021 patch.
- Vasculitis causes killed enemies to explode into tears that will damage other enemies. Unfortunately, while they inherit most of your tear effects, they don't inherit your damage and thus their usefulness drops off significantly in later floors, not to mention there are several desirable tear effects that the tears can't inherit, like homing tears. Perhaps the biggest problem with the item, though, is that the color of the tears is near identical to red enemy tears, which will likely cause a lot of confusion, especially considering numerous enemies already shoot out red tears upon death to begin with.
- TMTRAINER invokes the concept of Game-Breaking Bug to a degree never ever seen before. Picking it up seemingly does nothing… until you find an item. The items you will find in the run are completely glitched, and become random combinations of 2-3 item effects, alongside randomly activating based on certain events (room clearing, killing an enemy, taking damage), and either being active or passive items. You may probably guess where the item is going, and yes, it is perfectly and completely capable of activating any undesirable effect, including from the ones in this page, from self-damage by using the item, to summoning Damocles' sword ready to kill you from the first screw-up, to outright dying ala Plan C after killing an enemy. This item also stars in a hidden challenge that is essential for getting 100% Completion, meaning you'll at least get a taste of just how chaotic it can be. Good luck.
- Originally, plot-relevant itemsnote were also affected by TMTRAINER, meaning your run was practically guaranteed to end early if you ever pick TMTRAINER up — this resulted in a softlock in the pre-ascent version of Mausoleum/Gehenna, as there was no way to progress without picking up Dad's Note… which was glitched and unusable. Edmund later clarified this was a bug, and to the relief of one too many, it was fixed as of the November 2021 update, meaning these items are now fortunately safe from the effects of TMTRAINER.
- Lil Portal is a familiar that can deal damage, consume pickups, and spawn portals that lead to unexplored rooms once enough pickups are consumed. While sounding inoffensive on paper, in practice it has several faults that make it a widely hated item by the fanbase. It is easy to have it accidentally eat a consumable that the player may have wanted, such as a rune or a rare card. The portals spawned are also permanent and ignore room pathfinding, meaning it is possible to be softlocked if a portal that leads to a dead end appears blocking the only way forward in a level.
- Shard of Glass was an item added in Afterbirth+ that had the extremely underpowered effect of giving you a chance to drop a red heart and gain the effects of Anemic for the room upon taking damage. Like many boring, weak items, it received a face-lift in Repentance. However, the rework Shard of Glass got made far more annoying to use. It now causes you to begin bleeding upon taking damage, which spews a stream of blood tears that spray roughly in the direction you shoot. However, every 20 seconds while bleeding you will lose half a red heart. The bleeding only stops if you pick up a red heart or have no red health left. This adds the threat of a constant drain on your health while the effect is active, and if you have no Soul/Black hearts the effect CAN kill you. Plus, the blood spray can knock aside bombs, making it really hard to find secret rooms or blow up tinted rocks. All of this extra stress comes together for an upside that's really not even that great, especially since it's literally useless if you don't take damage or have any red health to begin with. Many players avoid Shard of Glass so they don't have to deal with this health management minigame for the rest of the run.
