When you first fire up Dead Space (and I do mean "when," not "if"), you'll be struck by a nagging feeling that you've played this game before. That feeling doesn't go away. It fades, mind you, but never completely.
It's like that nagging feeling, after you've left the house for a vacation in the Caribbean, that you've left the toaster plugged in. By the time you get to the airport, after obsessing over the phantom toaster for however many miles, you get distracted tracking down the appropriate gate, looking innocent in front of the TSA guys and trying to find a potty before they cram you in the tin can. Then come the free sodas and snack mixes and you maybe start to relax and think about the beach, wondering if you shouldn't have taken a later flight to ease your fears of burning down the house.
By the time you get to the beach, you realize it doesn't matter and start to hope the house burns. You hope someone robs the joint, then burns it down, planting fake bodies inside so you can pretend you're dead and never leave the beach ever. Dead Space is just like that.
At the start of the game you're treated to an in-game cinema sequence explaining the premise: You're aboard an interstellar tow truck sent by a major corporation to find and repair one of their faulty mining ships, the oldest and largest "planet cracker" in service, the Ishimura. Naturally, when you arrive on the scene things are not as they seem, and by the time you make for a landing all hell has broken loose. Spare, unenergetic SF writing at its finest. The fact your protagonist is named Isaac isn't just a limp-wristed nod to the master. These folks actually seem to get it.
After five minutes of playing you'll deduce that Dead Space is BioShock meets Doom 3, and you're not wrong. Dead Space's moody visuals and wet-your-pants scare tactics borrow heavily from id's failed experiment in horror gaming, but that's only because Doom 3 itself borrowed heavily from horror films, and just because it failed to capitalize doesn't mean you should condemn the source material.
In fact, let's pretend Doom 3 never existed, that id never tried to make monsters jump out of closets and that it didn't create one or two truly thrilling game moments and then repeat them over and over until the experience became as half-heartedly exciting as watching your granny strip naked.