I've also set October stream slots aside for horror games (F.E.A.R., Amnesia: The Dark Descent, SOMA).
I actually nearly forgot I meant to reply to this *dooh*
I don't think SOMA is a game for you to be streaming -- SOMA ... makes you pretty uncomfortable with implications of some of things you are doing. I think it is a game best enjoyed with the time to meditate of that discomfort and lends itself poorly to interaction with the an audience at same time.
A:DD on the other hand, I would really recommend to play with an audience, because in later stage of the game the atmosphere can be ... oppressive (I never finished this game because never quite could bring myself to progress because I got to a point where I honestly when "I live in this hole now, and that's my best life") and to get over that, going out an quipping with an audience might work.
I also would recommend that you give Othercide
a look if you are in for some comsic horror-eque game. I know X-Com-likes might be a bit outside your wheelhouse... but it is really good. (except maybe for the unexplicable, impractiable footware