YMMV / X-COM: Terror from the Deep

• Good Bad Bugs:
  • Especially on higher difficulty levels, Artefact Sites and Alien Colonies don't have enough spawn points for all the aliens, meaning that some of their terror units probably won't appear, which is just as well because those missions are very difficult as is.
  • Aliens armed with drills aren't programmed to use them. Again, the game is already difficult enough, so some players see this as a blessing. OpenXcom fixes this.
  • The Bio-Drone has a powerful melee attack, but only a 0.9% chance of hitting with it, most likely due to a design oversight. This means it is very likely to waste its turn flailing ineffectively at any adjacent Aquanauts instead of just shooting them.
• It's Hard, So It Sucks!: The considerably ramped up difficulty is considered the game's biggest flaw and has made it age less gracefully than its predecessor.
• It's the Same, Now It Sucks!: While well-liked enough for providing "more X-Com" with some new features, it's not the most well-respected installment in the series for being basically a Mission-Pack Sequel where everything has been arbitrarily relabeled to fit the new setting.
• Obvious Beta: Terror From the Deep was made by recycling a large part of the coding for the previous game which, although saved some time and money on development, meant that some serious and inherent issues would crop up during a playthrough.
  • It has a lot of crippling bugs. Xcomutil patched most of them, but you get goofy stuff like soldiers disappearing on 2-step missions if they get knocked out, base missions where you can't find the last alien, and the "Tasoth commander bug".
  • Additionally, there are nonsense impediments to some of the important research tree, which lead to more bugs, which aren't game-ending but still make the game needlessly more difficult and time consuming. You need a live Deep One to research Ion Armor (the equivalent of the Power Suit from the original game), so if you roll unlucky and aren't aggressive enough, you may not see ion armor (and subs) until very late in the game since Gillmen quit running terror missions after a couple months.
  • The "Updated Pathfinding AI" in OpenTFTD should make the Cruise Missions etc. a bit less tedious. Warboy discovered that the original algorithm wouldn't let aliens make two 90 degree turns, so that's why the game had so many "closet campers."
  • Converting the unlimited-ammo Laser weapons to limited-ammo Gauss weapons led to a very annoying program oversight with the Gauss Coleacanth.
  The Coelacanth/Gauss does NOT return any remaining ammo to your stores at the end of a mission. In addition, when you assign a Coelacanth/Gauss to a troop transport, 50 Craft Gauss Cannon rounds will be immediately deducted. These rounds cannot be refunded by any means. If you change your mind about assigning it, deassign it, and then reassign it, the premium will be deducted yet again from your stores.
• Sequel Difficulty Drop: Yes, despite its reputation, the game is easier than its predecessor in some aspects:
  • X-COM armour is more effective, at least if you're not shot from the side.
  • Tasoths are not as strong as their equivalents in the original game, the Ethereals because only Tasoth leaders have psionic abilities (whereas all Ethereals do), and they can't fly.
  • More aliens have glaring weaknesses. For example, Lobstermen drop like flies to melee and stun attacks, while Triscenes and Tentaculats can be neutralized with a single grenade or stun bomb.
  • Your troops now have access to powerful melee attacks.
• Sequel Difficulty Spike:
  • Early versions of the first game had a bug that enforced low difficulty mode - every time the player saved and then loaded the game, it would dial the difficulty back to the easiest difficulty. Due to complaints from high-level players that Superhuman difficulty was too easy, the sequel had the challenge rating cranked up across the board. In addition, while the first game only had one two-stage mission (the final assault), TFTD has many: ship terror missions, alien base attacks, and Synomium sites. And the last mission has three phases.
  • While most weapons in the game are simply equivalent versions of prior XCOM weapons made for underwater combat, there is no equivalent substitute for XCOM's laser weapons that had infinite ammo. All guns in TFD require ammo, which makes the item limit on your troop transport ships far more difficult to manage.
  • Bases are always staffed with a mixture of species, so it's not like you can run an early game Commander capture (not that you will survive a base assault in the early game, anyway). Furthermore, the sheer number of aliens in bases that have molecular control ability makes them nearly impossible to assault before you have your own MC lab. Alien bases are also far larger, and have far more enemies then the first game.
  • Tentaculats, this game's version of the Chryssalid, is a much bigger threat. Unlike the Chryssalid, they can fly, meaning flying armor no longer protects your troops from them. This also means they can ambush your team by coming over walls and other various obstacles, making it much harder to spot them in time. Oh and every single Alien Colony and Artifact site has several of them. Fortunately, they are an exclusively underwater alien, meaning you don't have to worry about them turning civilians against you on terror or cruise liner missions.
  • Getting the most advanced armor requires capturing a live Deep One. While this seems simple enough, the problem is Deep Ones are only available on certain mission types, in which involve certain enemies (Gill Men). This means having to rely very heavily on RNG to get a chance to capture one. While Gill Men commonly show up in the early missions, they become less common as the game goes on, meaning if you miss the chance to capture one early the game, you could be stuck waiting dozens of hours for a chance to nab one later, all the while being forced to take on the game's toughest enemies with nothing beyond Plastic Aqua Armor. Trying to capture one early in the game has its own problems, due to your soldiers lack of experience and the lack of technology to make capturing enemies easier.
  • Rank-and-File enemies are now commonly armed with Disruptor Pulse Launchers, which can easily wipe out your whole team in one shot. In the previous game, only the highest ranking aliens had weapons this powerful.
  • In the first game, aliens would only use grenades if your team members were grouped close together. In this game, aliens armed with melee weapons will routinely throw grenades at you whenever they are outside of melee range, even if your team is spread out.
  • Port attacks and cruise ships now have aliens that camp within buildings or closets within Port attacks and cruise ships. This is partly due to the pathfinding algorithm not working with two 90 degree turns, creating a series of "closet campers". Additionally, towers can have their stairs destroyed, allowing aliens to remain safe in the top if the player hasn't yet researched flying armor.
  • The damage range for weapons is now 50-150% rather than 0-200%. While this makes weapons more predictable, it also means your unarmoured Aquanauts have practically no chance of surviving a hit from any of the aliens' sonic weapons (in the original game, there was a chance that an unarmoured soldier would survive even a Heavy Plasma hit if the damage roll was low).
  • Your starting tier weapons are generally weaker than their equivalents from the first game (except the Gas Cannon, which is actually better than the Heavy Cannon) and some cannot be used on land. Even the next tier of weapons, the Gauss family, are weak or useless against most mid to late game enemies.

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