[An4ximandros]

 Or: Not XCOM + Roguelike + Space Hulk

You play through randomly generated space ships, infested by robots trying to kill you. As you run around the corridors you level up and add talents (powers) to your characters. Ala Rougelike, in space.
This game absolutely does not hold your hand, there isn't even a tutorial, so you gotta Minecraft your way through it. I lost my first troop less than 3 mins in.
 
 You can get it here: http://www.steammarines.com/index.html
 The game is also on Steam Greenlight: http://steamcommunity.com/sharedfiles/filedetails/?id=92922196

[NGTM-1R]

So it's...Space Hulk, kinda?

[An4ximandros]

 In a way, yes.
You can blow up the walls; name your troops; make combinations from four different classes at the start, each with different abilities to earn and the sprites are easy to modify.

[Polpolion]

it looks kind of neat except it always crashes before I get to kill anything. :/