It's hard to pinpoint exactly what gives me that impression. It's not one specific element of the game, but rather the way all of Dead Space's facets fit together in the package. Graphically and stylistically the game is designed to put you on edge. It's not comfortable. You're an everyman, trapped in a spaceship overrun with zombie-like aliens. Everything feels very gothic and dark. Even the main character's space suit makes him look monstrous.
You've heard about the menus before, no doubt. How they pull you into the game by being a part of the game world. I could've spent hours navigating those holographic projection menus, watching Isaac's head move as he watches you check out your inventory, almost voyeuristicly. Item drops appear similarly, with a holographic window appearing as you approach, showing what's on the ground. Again, these exist in real space and can be seen from all sides as you rotate your camera around.
As for gameplay, Isaac moves very fluidly and, for an engineer, has a surprising amount of firepower. Not just weapons, which are all based on engineers tools (I'm looking forward to getting more hands on time with the buzz saw), but also his ability to place enemies in stasis for a short period of time as well as a telekenesis ability. It's not certain whether these abilities belong to Isaac himself or to his suit, but no doubt we'll find out when the final game drops next month.
The developers at EA Redwood Shores are clearly conscious of the fact that getting lost in a survival horror game can be a deal killer. The Ishimura (the spaceship on which the game takes place) is well mapped, for the most part, meaning that Isaac knows where he's headed. Press the right stick in and a beam of light will shoot out and show you where you should be going. Hopefully this will keep the game's pace up, meaning less aimless wandering and more zombie alien decapitation.
You'll be doing a lot of decapitation. The combat is such that enemies will keep coming for you unless you remove their head. Your weapons are all designed to cut and slice, so you'll see limbs come flying off constantly. There's one enemy which has a bloated arm full of explosives, which detonate if you get too close. Of course, if you're a good aim you can dismember the arm and pull it towards you using telekenesis, only to shoot it back at the creature and obliterate them both. In anti-gravity areas, you'll see detatched limbs float slowly by, adding to the eerieness.
In anti-gravity areas you're able to jump from wall to wall. Each time the camera realigns as if you wall you've jumped to is now the floor. This is incredibly disorientating and will no doubt take a little while to get used to. It's especially difficult when you've got floating aliens screeching at you and flying in your face. In the anti-grav room in the demo I played I was given the task of destroying a set of boulders, which were floating around the room, by throwing them into a nearby energy beam. Thanks to Isaac's telekenesis powers, this was easily done. A nearby corpse also got a free trip to Energybeamsville.
Once all the boulders were destroyed and a switch was flipped gravity returned to the room, which then flooded with aliens from all sides. Sadly, they were too much for me and as Isaac died I was left wondering where my leg had floated off to. Dead Space looks like it'll be pretty scary. There will certainly be some "oh ****" moments as rooms become infested with aliens. I'm also hoping there are some more intimate, psychological scares coming in the final product. I'm looking forward to finding out when the game releases on the 14th of October. So soon I can almost taste it.