This was the first of a set of games that I played only at night time with headphones on at very loud volume...I was made to jump quite a lot and had lovely dreams about necromorphs for a while afterwards, so totally worth it!
Anyway I got this for the Xbox360 like a lot of my games, and I hadn't played the first one before. A friend told me that this was better than the first one anyway and I do plan to play through the first one at some point if I can get it cheap enough, anyway the fact that I knew very little about the first didn't really affect the gamelplay at all. Any little story elements carried over are pretty much explained so you're not missing out much if you haven't played the first like me.
This is a pretty cool horror/sci-fi/shooter game which is an awesome combo in itself. There are also puzzle elements to it which are mostly really kick ass. The weapons system (mainly aiming) is reminiscent of Resident evil 4 onwards which is another cool point really. The weapons are all upgradeable and can be pretty gruesome, my favourite is the spear launcher thingy as you could stick enemies to walls and rip off limbs and heads etc.
Quite a long game (kinda) it's on 2 disks which is always a bonus, it has very good replayability as it has a new game + option which I was going to start last night but I got distracted with dredmore...curses.
If you are into horror shooters then you should certainly have a go at this game as it's just awesome :D