Very good game
The squad system where you switch back and forth between different characters to make use of their abilities is cool enough. Its a nice twist on just giving the one main character every single ability. The abilities themselves are pretty cool too. The only thing is that there really is a bit of a learning curve while you play the game, and I would expect to get overwhelmed by monsters at first a bit until you get everything down. Don't expect to just run through this game guns blazing because you'll be dead quick.
To me though, the bread and butter of this game is both the story and the atmosphere. You really have to like this sort of thing to have the game stand out as anything different because underneath it all, it is still "just" a FPS. The twisted environments, monsters, and story are what is going to make you either love or hate this game. This is not a horror game in the sense of something like Condemned where it is gory for the sake of being gory. This game has horror elements from movies like Hellraiser, and the gore serves a purpose in this game. Things are just "that way". You are in a hell and things look accordingly. For as creepy and gory as this game is, I don't feel there is any sort of un-necessary gore going on at all. This game is very tastefully done.
Technically the game has some black marks. The graphics are good for the year it was released, but its nothing revolutionary. Another problem (at least on the PS3) is the framerate can get inconsistant at times. Its not as bad as a huge multiplayer battle in KZ2, but at times, it gets pretty slow for a moment. Its not "that bad" though, more of an occasional irratation. The music and sound in the game is all top notch, no complaints there.
All in all, if you go into Jerchio expecting an early residnt evil "make you jump" sort of thing I think you'll be dissapointed. If you go into it looking for a squad based military shooter you'll also be dissapointed. This game seems to cater to a niche market, people who like the 90's style horror movies and books. If you are a Clive Barker fan, I can't see any reason why you wouldn't like this game.