This is the kind of game Doom 3 should have been.
It took me 6 hours to beat the single player game and i'll tell you this: there will be a sequel.
Graphics: Prey uses the Doom 3 engine to it's full extent to create a bio-mechanical alien dyson's sphere where organic alien flesh comingles with advanced alien technology. The characters are well detailed, though some of them do look like action figures like Tommy's Grandfather. Your weapons are mostly organic and glow in the dark. Don't worry about dark areas, you have a lighter on you at all times unlike Doom 3 and most of Quake 4.
Sound: The sound is excellent. The voice acting is good, except for Tommy who I wish would shut up when there is no one to talk to.
Is Prey worth the wait? I'm definitley saying yes. This is the game to get this summer.