Since TFTD uses the same engine as UFO Defense, I have a few things I would like to see for TFTD. While most of it is from OpenXcom of UFO Defense, I'm listing a few things that are for TFTD:
1. Land Alien Craft Battles: You cannot shoot down alien subs while they are on the surface, but you can assault alien subs that have touched down on land. This should trigger a land craft assault using environment depending on the location on land, some environments borrowed from UFO Defense. If the craft that has landed on the ground is a Battleship or Dreadnought, you will expect to face land terror units associated with aliens. And as with all land battles, your aquanauts will have their helmets off and can't use water only weapons.
2. Land Alien Colony Battles: Some alien colonies are placed on land, and launching an assault will trigger a two-stage battle on land with alien structures unchanged from the vanilla version. Both outside and interior are on the surface and you will expect land terror units and be unable to use water-only weapons.
3. Final Phase of T-Leth Assault: When you reach the third stage of the assault, there will be a message saying: (You cannot save in the middle of this final battle. Do you wish to save at the beginning now? [Yes] [No]). Yes will take you to the save screen.
4. Tentaculats: The Chryssalid of TFTD now appears on land and water, sometimes on alien surface (terror) attacks, turning humans into zombies. On land, however, tentaculalts cannot fly.
5. Sonic Pistols: These weapons should in OpenXcom have the autofire function as well as aimed and snap, but the Sonic Blasta Rifle and Cannon remain with just snap and aimed. Aliens may overwatch with these with snap or auto.
6. SWSs are now vulnerable to stun: SWSs take .7x from stun weapons, but if dealt enough stun damage, the SWS will cease to function until the stun wears off enough. If the battle is won before the stun wears off, the SWS will be recovered and can be used again.
7. Gauss Cannon separate ammo: The Colecanth/Gauss and the Craft Gauss Cannon each use their own ammo, both of same cost. The Colecanth/Gauss uses Gauss Shells and the Craft Gauss Cannon uses Craft Gauss Shells.
8. Human deaths screams: I would like there to be the usual death scream for male humans and a different new death scream for female humans.