Is fantasy, not science fiction.
I played the game entirely, and I don't recommend it until a much needed patch is available.
The game really gets no benefit from PhysX (I buyed the game hoping to play a game physx capable).
And the performance is really poor. I was forced to play it on 1024x768, without any antialiasing, on a Geforce 8800 GT oc, and still got lots of glitches, and bad framerates.
The sound frequently ruined itself completely, and sometimes crashed.
Sometimes you get stuck on places, and finds yourself incapable of progressing. Then reload an older saved game, and finds that you got stuck because of a bug, instead a by design game. Sometimes a tube bends too vertically, and you cannot escape a room, or fix it.
The savegame system is broken. Sometimes you save a game, but are unable to reload it, or reload it and after a looong reload time, just finds that the small screenshot and filename does not match what was showed, and you loaded another file.
Although the game introduces some welcomed original innovations (common First Person Shooters are getting really repetitive lately), all the bugs it have make playing it a really painful experience. I had good hardware, but my experience was poor, and was no exception. I found lots of people with the same problems on internet (although others had slower hardware than me, and got no problems).
I strongly recommend to wait for a patch to be released, before acquiring the game.
After it, I played FEAR 2. It was so much optimized software, and played so smoothly, even on max settings, that I really enjoyed it.