What builds have you completed the game with (including killing the final boss) and how do your experiences with different builds compare (both in the final fight and throughout the game)?
I'm asking because it actually took me a long time to get around to finishing a game. I have several characters that reached Tchort, but were unable to kill him - in the last case, I was actually under the impression that I had solved the mutagen puzzle when I actually didn't, and thus went into fully healthy Tchort's chamber under the mistaken belief that I'd have an easier time, but I didn't. Couldn't kill him. (There was also the psi build that I simply abandoned before the DC, although I might finish her up some time.)
Recently, however, I finally managed to finish the game. It was an assault rifle/sniper rifle build - not entirely optimal since I wanted to try out things on it that I haven't tried before (riot gear, Mercantile skill and the related feat), but it still certainly seemed like that a build like this is actually the optimal one for the Tchort fight. The sniper rifle could kill pretty much anything in 1 hit, and even though the mutagen tanks generally took two, even with W2C bullets, it was very helpful because I didn't actually have to enter significant tracts of the map to reach and destroy the tanks. The assault rifle was also insanely powerful - a 9-long burst, even with normal bullets, could kill a tentacle most of the time. The other times I tried this fight, I had much less impressively powerful characters (crossbow, sledgehammer...), and this just felt so much easier. On the other hand, this assault rifle fellow actually struggled for a while before getting established, while my psi-based character had a pretty easy time from the beginning until the point where I stopped playing her (i.e. throughout most of the non-DC parts of the game). I wonder how she would do against Tchort...