Note: Since TFTD shares its game engine with X-Com Enemy Unknown, there are many problems that are common to both games. Please track any shared/common bugs under the XCOM-EU list of Known Bugs (link at the bottom of this page). This page is just for TFTD-Specific bugs.

List of TFTD-Specific Bugs

Research Tree bugs

See the Research Bug Avoidance Guide for full discussion. *

Alien Glitches

Aliens can't use carried melee weapons (Vibroblades and both types of Thermic Lances), even when they are equipped with them. (This is a game engine bug is present in XCOM-EU as well, but it is not relevant to XCOM-EU, since in XCOM-EU aliens never get equipped with any carried melee weapons.)
The Bio-Drone's melee attack almost always has no effect, even on unarmoured troops. (Zombie has determined the weapon has a base accuracy of 0%, presumably a programming error). This is a serious flaw in the Bio-Drone, as it always uses this attack when Aquanauts are adjacent - especially given that one of the best ways to deal with Bio-Drones is by melee combat. *
The Hallucinoid's ranged attack only works on land, but the Hallucinoid rarely/never appears on land. Presumably this is a programming error and was meant to be the other way round (only works underwater). The melee attack works normally. *
The Bio-Drone leaves a burning trail (holdover from a Silacoid in UFO). *
The Deep One attack looks like the Celatid spit / mortar (holdover from UFO). *

Mind Control Bugs

Large units in TFTD suffer from even more bizarre behaviour than in UFO, due to an attempt to fix the old UFO bug.

Craft Bugs

The floor maps & schematic pictures of the Survey Ship and Escort are swapped with each other in the Battlescape, the Interception window and the UFOPaedia. There is a (partial?) fix for this in XcomUtil. Zombie has provided a fix that also fixes the routes as well as the maps.

The schematic pictures of the Battle Ship and the Fleet Supply Cruiser are also swapped in the UFOPaedia and Intercept window. The floorplan maps on the Battlescape are not affected.
Troop transports like the Triton can be blown up quite badly in land maps (rather than being invulnerable as it should be). This somehow doesn't prevent X-COM from flying back using it.
TFTD V1.0 There is a unit positioning bug when placing 26 men in a Leviathan. This bug is fixed by XcomUtil (and presumably in later versions of TFTD).

X-COM Equipment Glitches

Underwater-only weapons (HydroJet Cannon, Torpedo Launcher, and Disruptor Pulse Launcher, plus the Coelecanth/AquaJet & Displacer/PWT SWS weapons) are able to fire on land during XCOM's reaction-fire phase. This should not be allowed. *
Coelacanth/Gauss Cannon ammo arming bug(s): 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. *

Geoscape Bugs

There is a really annoying "Cannot intercept over land" message that repeatedly pops up (often more than once a second) during some pursuits along coastlines. This is probably because the pursuing aircraft is moving rapidly from land areas to sea areas and back again as it flies along a coastline. *

When intercepting an Alien Sub that is too deep for an XCom Flying Sub's operating depth, the Sub will report "Mission too deep" and return to base, rather than tracking the Alien Sub until such time as the Alien Sub rises to a depth at which the Sub can intercept. This forces you to take control of the Sub and get it to follow the Alien Sub manually, using Geoscape waypoints. *

Alien Subs will sometimes Touch Down on land (e.g. several hundred nm south of the North African coastline). If you respond to these missions with an Assault, they are fought at Shallow depth rather than on land. Geoscape map/terrain data bug maybe?

Manufacturing Rate Limit Bug/Quirk (TFTD) - The manufacturing windows allows you to assign more technicians than the limit allowed and provides a quicker estimated time to complete the project than actually occurs. *

Battlescape Bugs

Strange MCD records (aka the 3d shapes that form the various walls and objects in the game). Due to some strange shapes, there are some locations with various line of sight errors and clipping errors such as a bullet hitting something in mid air when it shouldn't. There are even some cases where walking into a tile is much more tiring than it should be. This is not TFTD specific, but is much more apparent.

On ship missions, there are some metal panels on walls. These tend to remain floating in the air even if the wall is destroyed. This is only a visual bug.

Multi-stage mission bugs
- Strange effects occur to Aquanauts who were unconscious and/or under Molecular Control at the end of the previous stage of a multi-stage mission. These effects include: the Aquanauts becoming invisible, or becoming 'wraiths' in the next mission stage. (Does this also affect XCOM-EU, e.g. the 2-stage Cydonia mission?) *
- Any Captured aliens that are carried will die when they reach phase two. The actual working logic behind this is that since the new map is generated with a new set of enemies, the 'stats' that make up the stunned alien aren't retained, but only the physical object that represents the alien is carried over. This makes capturing aliens on the first part pointless unless you intend to abort the first part after physically hauling the stunned alien back to the transport.
- TFTD V1.0 any equipment that is left on the ground on the first part of a two parter mission are not collected when you abort or complete the second part. This includes everything in the troop transport, which is lost forever. The V2.0 patch fixes this bug and returns everything on the first map.

Dye Grenades are to all intents and purposes, useless. Arguably not a bug, but it should not have survived basic playtesting. Weak weapons (eg Dart Gun) are one thing, but Dye Grenades are pointless because they never generate enough of a screen to block visibility. The best they would do is reduce alien visual range from 20 to 17. There would be a strong case to fix the strength of the Dye 'explosion' upward from 10 to 60 (like the Smoke Grenade) or at least 30-40. *
Stunned Aquanaut bugs. (These might not be specific to TFTD, the situations are rare enough).
- In some cases, when moving a stunned body elsewhere, and it is subsequently killed by an explosion, the corpse may appear back at its original location. *
- Stunned Aquanauts in the Triton are not reported as either inside or outside the transport sub when you abort a terror mission. *
- It is possible to abort a mission even if all Aquanauts are stunned. Not sure if this should be possible?
- If the Triton is lost (aborting with no survivors), the stunned Aquanauts are shown as assigned to "Weapon-1", not their Triton, and they become inaccessible, basically lost/gone. *
- The animation for stunning a Civilian falling down shows them being violently killed.

Manufacturing Rate Limit Bug(TFTD)*

In UFO Enemy Unknown, the Manufacturing Rate Limit is just an irritant: The game prevents you from allocating more Engineers than the PRODUCT.DAT files says are needed to complete the item in one hour. This result in a minimum of one hour per item being necessary for the whole order. In an attempt to overcome this, the programmers eliminated this cap on the manufacture screen but failed to alter the code that actually determines what is produced every hour. Any extra technicians assigned over the number shown when you start an order produce nothing and their hours are wasted.

Ufopedia Discrepancies

Deep Ones are portrayed carrying a weapon, in fact it appears to be carrying an X-com issue PWT Launcher craft weapon, instead of being unarmed other than its built in attack. *
- Also, it is colored Green in the Ufopedia (due to tinting provided by the water), whereas it is mainly whitish grey with a pink trunk in the Battlescape.
The Tasoth species is described as more resembling some sort of foot soldier in Ufopedia. It seems highly likely that the Tasoth were supposed to be one of the grunt races, and planning issues caused there to only be 4 main races in TFTD, making Tasoth the default Psionic (MC using) race.
The Tentaculat description says that it transmutes its victims into mindless things (Zombies). Ok. But then it goes on to claim that these progeny (Zombies) cause death by touch even through armor. That's very wrong. The resulting zombies have a rather weak melee attack, especially compared to the Tentaculats. Also, the description says nothing about Zombies turning into Tentaculats upon death. That seems to be some leftover from EU.
The Ufopedia shows the damage of a Displacer/Sonic cannon as 130, but the coded value is 110. *
The Hallucinoid is described as having a ranged stunning attack, but it does not have one. *
See also the Craft Bugs where the map layout, interception picture and the Ufopedia picture are inconsistent with each other.
The Ufopedia describes the Dart Gun as having a ten round magazine, when in fact it has a twelve round magazine.

Questionable logic

Aquanauts and SWSs are unable to move vertically in water without the use of alien technology. Apparently no one has heard of ballast belts, propellers, or flippers.
- Actually, most of the aliens are unable to move vertically in water, despite most of them being aquatic creatures!
Thrown objects behave underwater with identical physics as on land - impossible.
Explosions behave underwater with identical physics as on land - impossible. (See this link)
Projectile weapons behave underwater with identical physics as on land - extremely unlikely.
Vehicles behave the same underwater as in the air, fuel, acceleration, speed, etc. - impossible
Alien "Molecular Control" is said to work via MC implants on the subject, but works on human Aquanauts (and civilians), regardless of whether the humans have MC implants. (They should've just called this Psionics like in Enemy Unknown.)
X-com craft mounted Gas Cannon has an effective range of 8km. A gas reservoir capable of launching a solid bolt 8km underwater? - ridiculous.

XcomUtil Bugs

These bugs relating to XComutil may be outdated.

Gillmen are reported as Snakemen in some pop up messages, when using XcomUtil.

Sometimes at the start of the 2nd level of a mission, all items, not loaded onto Aquanauts in the equip phase, appear to be lost. And some/all weapons have an ammo count of zero / no clips (possibly when the ammo was loaded automatically in the equip phase). (Believed to be related to XcomUtil teleporting 'spare' equipment back to base at the end of a level. See Talk page and Talk:XcomUtil#Open Bugs)

TFTD Extender

Items marked with an asterisk (*) have been fixed with the Extender.

Known Bugs (TFTD)

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