I added this game to my collection today, and have been playing it for the past 2-3 hours or so, totally enthralled. Runs smooth as silk on my middle-of-the-road 1.1 ghz/32MB GF2 system at 1024x768/32 bit. I agree with Palooka, I instinctually stop moving forward when the music picks up, and thus far, that's made a couple of critter attacks rather anti-climactic. (I've just entered the weather station in pursuit of the Norwegian with the radio.) But all in all, this is the scariest, most atmospheric game since System Shock 2.
But am I the only one who's disappointed that there's no multiplay in this game? The individual roles would have made co-op play a blast. Or envision a 4 on 4 deathmatch, with or without the wildcard of AI monsters that hunt down any humans they can find. An editor would have been nice too--with the talented scripters around these parts, we could have had a nice "ghost stories around the campfire" feel playing one another's maps. Just minor quibbles, though--all in all, the game is a blast thus far.
Side question: does anyone know if your squadmates are programmed to transform into Things at set times? I just had my engineer (the Southern guy) turn, and after I dispatched him, I got assaulted on all sides by a big fella and a whole bunch of the spiders. Could I have protected him to have some backup there?
Edit: just read Garrett's initial post more carefully--is it actually random? My second medic (the guy from the cafeteria) transformed every time at the same place, and I had died and reloaded three times.