This is an amazing game. It has borrowed some of the mechanics from Bioshock, but it is nowhere near a "Bioshock in space". Where bioshock has offered you a wierd and twisted sense of dementia, this game offers a cold hard fictional reality of deep space. It is gritty, dirty and bloody in right amounts. It gives you that feeling of palpable reality that you can almost taste. If you are a fan of Event Horizon, Alien etc, you will love this game.
The camera is over the shoulder 3rd person, which adds to the atmosphere of something lurking just behind your back and you not being able to clearly see it. One of the greatest additions, which I want to see in all games from now on is the complete integration of GUI into the gameworld. There is no button that takes you out of the game, everything you do, wether browsing your inventory or checking your map is done within the world. All readings like health, air etc are integrated into your suit so you have nothing that detaches you from the world. It is amazing how an apparently simple thing as that can add to the game atmosphere.
And the atmosphere is scary, confined and claustrophobic. Parts where you go to 0G are downright disorienting in a right way, being that you are able to walk on ceilings and walls, you can easily lose the feeling of what is up and what is down.
Most of all, the game is not a run on the mill copy of something else, it just reeks it's own unique character at every step.
Only thing that goes against it is that it is released so close to the major franshise titles like Gears 2, fallout 3 that people have been waiting for years, and so it might get under the radar for alot of people and not get all the attention it really deserves.