History VideoGame / TheBindingOfIsaac

* {{Feelies}}: The Nintendo Switch boxed release includes a fully illustrated instruction manual, which parodies the original ''Legend of Zelda'' game manual, as well as some stickers featuring some of the game's characters and enemies.

* BlackoutBasement: The Curse of Darkness results in the entire floor becoming darkened save for a circle around Isaac, making it difficult to spot enemies or hazard from a safe distance or finding tinted rocks. There are two ways to lift it: using the card "The Sun" or picking up the Night Light. The latter has the benefit of defanging the curse even in floors after it's picked up, thanks to the light beam it emits.

* WeAllDieSomeday: One of the random fortunes from the Fortune Telling Machine simply reads "WE WILL ALL DIE ONE DAY".

* WeAllDieSomeday: One of the random fortunes from the Fortune Telling Machine simply reads "WE WILL ALL DIE SOMEDAY".

* WeAllDieSomeday: One of the random fortunes from the Fortune Telling Machine simply reads "WE WILL ALL DIE SOMEDAY".

* GlassCannon: ''Afterbirth'' added a literal Glass Cannon, which grants a powerful, reusable shot but also reduces Issac's health to just half a heart. A patch nerfed it so it takes away all red, soul, and black hearts. ''Repentance'' overhauled the item: now it doesn't affect health directly, but taking damage while holding it breaks it until it recharges, and Isaac takes increased damage and trails creep for the rest of the current room.

* GlassWeapon: In ''Afterbirth'', you can find the Glass Cannon, which is exactly what it sounds like, in [[GlassCannon every sense]]. It's incredibly powerful, but lowers your health to just 1/2 of a heart when used, meaning that you'll be killed in a single blow if something hits you. ''Repentance'''s overhaul emphasizes the "glass" part, as instead of depleting health, it shatters after Isaac takes damage and needs to wait several rooms to repair itself. The sharpness of the cannon breaking also makes Isaac take more damage and bleed on the floor until he leaves the room.

On June 27, 2018, a Kickstarter page for [[https://foursouls.com/ The Binding of Isaac: Four Souls]], a card game published by [=Studio71=], was launched, and was successfully funded. Another successful Kickstarter page was launched in June 2021 for a massive expansion with the subtitle ''Requiem,'' bringing with it the new content from ''Repentance'' as well as a plethora of crossovers with other franchises, from games like ''VideoGame/CaveStory'' and ''VideoGame/AmongUs'' to even non-video-game works such as ''Film/PGPsychoGoreman'' and ''Film/TheRoom''. The expansion is currently planned to be released at some point in early 2023. A digital version of ''Four Souls'' is also officially available as a [[https://steamcommunity.com/sharedfiles/filedetails/?id=2501791757 Workshop item]] for ''Tabletop Simulator''.

* StatusEffects: The Iron Bar item adds a Concussion tear effect, which confuses enemies. The Charm tear effect causes enemies to actively seek out and damage other enemies, if they are capable of doing so (enemies stuck on a certain path, such as rolling guts, don't seek out other enemies); the charmed enemy can still damage you, however. The Fear tear effect causes enemies to slowly run away from you, and stops some enemies from firing at you. The Fire tear effect deals some brief continuous damage after hitting an enemy, and causes occasional fiery explosions. The Slow and Poison effects return from the original game. They're unchanged except affected enemies now have an icon above their heads.

* AsTheGoodBookSays: ''Rebirth''[='=]s title theme is titled "Genesis 22:10", which corresponds to the verse, "Then he reached out his hand and took the knife to slay his son."

* ReligiousHorror: All throughout the game; the game starts with a fanatical mother hearing voices she thinks are from God, and continues with the titular Isaac fighting off various monsters, demons, and other horrors inspired from Jewish and Christian myth and legend (mostly but not only Literature/TheBible).

On June 27, 2018, a Kickstarter page for [[https://foursouls.com/ The Binding of Isaac: Four Souls]], a card game published by [=Studio71=], was launched, and was successfully funded. Another successful Kickstarter page was launched in June 2021 for a massive expansion with the subtitle ''Requiem,'' bringing with it the new content from ''Repentance'' as well as a plethora of crossovers with other franchises, from games like ''VideoGame/CaveStory'' and ''VideoGame/AmongUs'' to even non-video-game works such as ''Film/PGPsychoGoreman'' and ''Film/TheRoom''. The expansion is currently planned to be released at some point in 2022. A digital version of ''Four Souls'' is also officially available as a [[https://steamcommunity.com/sharedfiles/filedetails/?id=2501791757 Workshop item]] for ''Tabletop Simulator''.

** ''Repentance'' nerfed the Converted from having an unlimited use to being a three-charge item, to prevent abuse from certain characters.

** Plan C takes it a step further by [[SmartBomb instantly killing everything in the room]]. Including Isaac.

** [[spoiler:Isaac/???]] got a bullet hell buff and new attacks. However, Isaac's third form is [[InvertedTrope considerably easier]] in ''Rebirth'' — his light attacks are easy enough to avoid as you can guess the pattern of the safe zones, plus his bullet hell attack has a much shorter range, is easier to dodge, and is not homing. and he doesn't spawn angels in this phase.

** Most characters receive an upgrade to their starting load out once certain conditions are met, such as Cain starting with the Paper Clip (unlocks gold chests for free) or Eve starting with the Razor Blade (boost damage for the room at the cost of a heart, letting her trigger Whore of Babylon at will).

** The 12th Ending gives us our very first sign that the story we’ve been told is not what it seems [[spoiler: when Isaac goes into the chest.]]

** ''Afterbirth+'' has the Plan C item, which inflicts massive damage (it's enough to kill the TrueFinalBoss 100 times over) on all enemies in the room, and then kills you after three seconds. If you use it on (almost) any boss on their last lifebar, it still counts as a victory… but if you have no extra lives, it'll still end your run unless you can get into the end-of-run chest within those 3 seconds. If the boss you used Plan C on wasn't the last boss of your run, [[YouAreAlreadyDead you're toast]], no ifs, ands, or buts about it.

** One of ''Rebirth'''s Dice Rooms has the same effect as Forget Me Now. Unlike forget Me Now, using it does not force you to abandon a favored active item.
** The R Key, an item from ''Antibirth'' officially added in ''Repentance'', acts as a Forget Me Now for the entire run, resetting you at the start of the first floor (barring [[spoiler:the descent to Home]], wherein using it keeps you in the current game state) with your character build intact.

* TakeYourTime: There is no time limit of any kind, and you can backtrack as much as you want within a floor. Downplayed in ''Rebirth'', which has a Boss Rush room that's only accessible by beating Mom in under 20 minutes. Similarly, ''Afterbirth'' adds [[spoiler:an exclusive boss fight]] that requires The Womb to be cleared in under 30 minutes.

** The Liberty Cap still retains its oddball ability to sometimes act as a compass instead of a mushroom item.

** [[spoiler:The Blue Womb contains two Item Rooms, a Shop, and a single 2x2 room with Hush in it.]]
** [[spoiler:Home only has a replica of Isaac's house in gameplay, with no special rooms. Simply sleep in Mom's bed and go to the television to fight Dogma. It is a downplayed example in that the backwards trek through the previous floors is the "stage" and Home is simply the boss area.]]

** The unlock for beating [[spoiler:Hush]] with [[spoiler:Keeper]] is said character starting with a penny. Of course, you're earning that penny by killing what is arguably the hardest boss added in ''Afterbirth'' with a borderline JokeCharacter. (''Repentance'', for what it's worth, [[SubvertedTrope subverts]] this--that penny instead becomes a permanent third coin heart, something very handy given how difficult it is to get actual coin heart upgrades mid-run.)
** In order to obtain [[spoiler:Godhead]], you need to collect all the completion marks on Hard mode for a bonafide JokeCharacter, one of the hardest tasks in the game. It's a fantastic item that ranks among the best in the game, with tons of positive synergies, but if you can perform that well you may not need it when it does show up.

* DamageSpongeBoss: While there were already bosses who had this as their gimmick, this is taken to extremes as one of many gimmicks for the two new major bosses of ''Afterbirth'', [[spoiler:Hush and Ultra Greed]], who both have health that eclipses the health of every other boss in the game and even normalize the damage you deal to them, meaning that something that would one-shot every other boss in the game will only deal chip damage to them. ''Afterbirth+'' subverts this with [[spoiler:Ultra Greedier]], who has less health than [[spoiler:Ultra Greed]], yet plays this straight with [[spoiler:Delirium]], who doesn't need normalized damage because he has more HP than even [[spoiler:Hush]].

* DyingDream: [[spoiler:''Afterbith+'' reveals that the whole game is this (or not, depending on how ''Repentance'''s endings are interpreted). Even his mother attempting to kill him was allegedly imagined]].

** The Reversed Tarot Card "IV - The Emperor?" warps you to a boss room where you fight a boss two floors below the current floor, granting you an item and opening the boss door to take you back to the main floor if you defeat them. If you use this on Caves II or Mines II, you end up fighting Mom - but just like the normal Mom fight, the boss doors disappear after she's defeated, and ''un''like that fight, no hole in the floor spawns, leaving you trapped in the room if you didn't make an escape plan beforehand.

* GlassWeapon: In ''Afterbirth'' you can create the Glass Cannon, which is exactly what it sounds like, in [[GlassCannon every sense]]. It's incredibly powerful, but lowers your health to just 1/2 of a heart when used, meaning that you'll be killed in a single blow if something hits you. ''Repentance'''s overhaul emphasizes the "glass" part, as instead of depleting health, it shatters after Isaac takes damage and needs to wait several rooms to repair itself. The sharpness of the cannon breaking also makes Isaac take more damage and bleed on the floor until he leaves the room.

* LethalJokeItem: Because of the improved item synergies, many mediocre items can become the keystone to a weird yet highly effective setup. Bonus points if several if your items are bad but [[AllYourPowersCombined they become effective in tandem with each other.]]

* LOL69: The Sausage item added in ''Repentance'' increases the chance of finding a Devil/Angel and Planetarium by 6.9% each. Its internal ID is also 669 and its costume sprite is called "costume_069x_sosig.png.". Subtle.

** One of the new ideas added to the game is the possibility of crippling yourself by picking up a bad item early, Tiny Planet and Bob's Brain to name two, in the hopes that later in the run you'll pick up an item that goes complements them really well, such as a high attack speed or piercing shots for Tiny Planet to make it better than the pretty inaccurate item it is normally. One could argue it's part of what makes the game more fun than before, due to the sheer number of items that you might pick up and hold on to in the hopes they work exponentially well with another item you find on the run.

* MissingReflection: As of ''Repentance'', picking up Charm of the Vampire will remove Isaac's reflection from rooms with water (mostly the Downpour, Dross, and Flooded Caves). Also, Wraiths - which are normally invisible except for their reflections - become visible but have no reflection while in the Mirror world.

* MurderSuicide: [[InvokedTrope Invoked]] by a new item in ''Afterbirth+'', the Plan C. It instantly kills anything in the room (even final bosses)... and kills you shortly afterwards.