Dead Space is a cross between Resident Evil 4, Bioshock, and Half Life. You'll know what I mean.
Dead Space puts you in the role of Issac Clarke, an engineer who's job mainly consists of repairing spaceships, such as planet crackers. Planet Crackers are gigantic spaceships the human race use to mine other asteroids or planets for their resources.
When he is sent, along with two others, to respond to a distress call from the USG Ishimura, the largest Planet Cracker ever built, things take a turn for the worst. The crew of the Ishimura are all either dead, turned into Necromorphs, dying, insane, or dying AND insane (many insane characters become a part of the story). Necromorphs are the race of creatures you'll fight for the duration of the game. They are wonderfully designed, being menacing and scary. Most of them are morphed bodies of crew members or babies, but with blades for arms, or tentacles that shoot lethal spores, or on some occasions, stomachs full of smaller Necromorphs.
Alot of the game involves strategy. Some of the creatures are killed more easily by certain weapons, and some are more sensitive in different body parts. But the main thing to consider is strategic dismemberment. The limbs of every alien can be cut off to kill them much easier. If you went around only shooting these guys in the torso, you would run out of ammo fast. There are often times when you'll be clenching onto minute amounts of ammo remaining for your gun. That's when the game gets really intense.
There are plenty of scary moments in the game, and lots of scripted scary moments, but sometimes there are predictable and cheap moments with crappy scare tactics. They make you go, "Oh man, this game is starting to feel like a gay teenage horror movie...". But luckily, it isn't. The story is actually excellent. The game consists of 12 chapters, each one in a different part of the Ishimura with a different main objective. The story has twists, turns, and backflips galore, and plenty that catch you off guard and think you're watching something directed by Martin Scorsese (the twists are THAT good!).
Throughout the game there are stores, upgrade benches, and save stations. At stores, you can purchase weapons using credits found around the ship or store anything in your inventory in the safe. At benches you can upgrade your weapons or suit using power nodes found around the ship. Save stations are where you can save your progress, and don't worry. There are plenty all over the place.
Some sequences and puzzles in the game take place in Zero-Gravity. That's where alot of the fun comes from. You can jump from wall to wall, and sometimes get dizzy from the constant camera-flips and forget where down was in the first place. But in a good way. Other parts are in places that have no air. A timer will pop up and you have to wither leave or recharge your oxygen before the time runs out or you suffocate and die. And you sometimes have to fight enemies with no air. And it's so perfect, because all you hear is Issac's heartbeat and breathing, and when you shoot it sounds like shooting underwater. And you actually believe that that's what it would be like with no air.
Dead Space feels somewhat familiar. Actually, it is. It's a cross between Resident Evil 4, Bioshock, and Half-Life. Anyone who's played Dead Space and any one of those three games knows why, and you will to, when you play this. Because you have to. Because Dead Space is great.