I've finished the game... and I liked it (single player). I don't know what to say - it was just fun to play it. I love old FPS games where you have to collect health and armor, and I very much liked the fact this system was implemented here. Level design was OK, I liked the fact that levels were large and offered some space for exploration. Besides, since Raven level the design started getting better and better. Unfortunately, the first entry to Hadley's was, IMO, the worst part of the game, but after that (and before) it was all good. But I'm a fan of old school Doom and Quake-like long-corridor levels, so I'm probably in a minority here.
I liked the motion tracker and the fact it showed collectables - it made sense to use it. I liked the story as much, as I like some of the better Aliens comic books - when compared to movies, they suck horribly, but they're enjoyable on their own. I was really into the atmosphere. And as for the graphics (X360 version) - yeah, blurry textures here and there, but I don't mind that, as a guy who thinks Quake 4 is one of the best games ever and plays it every month. At least A:CM was smooth (with noticeable screen tearing only during some of the cut-scenes). I liked the fact everything looked "real", like it was used by people, not like some random scenery. I absolutely loved the look of W-Y labs.
I haven't really experienced bugs and glitches (well, an Alien froze here or there, and O'Neal fell through the floor of an elevator once). Although the A.I. was as simple as it could be, I died pretty often and I think the game was pretty challenging, at least for a post-CoD:MW game.
I'd like to see more audio diaries, some written diaries, more levels with just exploring without fighting - because the atmosphere was really, well, if not creepy, then at least science-fictiony and engrossing.
Bottom line: the only thing I care for in video games is how much fun they give me. They may be bugged as hell, but if I enjoy playing, I don't mind it at all (I think Skyrim fans will understand it). I enjoyed A:CM immensely, and that's why, despite technical difficulties, I give it 9/10.
By the way:
it's near to impossible to find real in-game screenshots on the Internet. Could someone start a thread where PC-version owners would post their own, undoctored screenshots? It would give us a chance to compare "official" screenshots with what's really in the game.