I finished Dead Space last night. The game has some flaws, most notably the repetitive feeling I was getting in the last 1/3 of the story, but the awesome cinematic presentation and solid core gameplay kept me hooked to the end. I'm looking forward to the sequel.
Cool fact: after you win, you get to play the game again with all your powerups! I love it! Why don't more games let players do this? Sure, it's a cakewalk, but it is really fun to steamroll the enemies that gave you such a hard time at the beginning. (It's like...revenge.) The game also coughs up a bunch of bonuses and an upgraded suit. I was very pleased. I don't know if I will play through the whole thing again, but I might just to check out the other weapons and so forth.