Dead Space is a third person shooter similar to Gears of War, with the ability to aim your weapon with the left trigger and fire with the right. There are also a couple melee moves including a good ole stomp.
One of the first things that surprised me was the absence of a HUD. No health meter, no ammo counter, no mini map?! The makers of the game found a creative way around it by using holographic images/video and status indicators on the suit Isaac wears. This small feature adds a lot more screen space to your display and a lot more visual "ambiance". Without the option to see when enemies are coming and not knowing where you're running when something is chasing you makes for a harrowing few moments.
Isaac himself moves kind of slow, kind of like a regular guy wearing a big heavy suit.
The weapons themselves aren't actually guns, they are mining tools, mineral cutters and energy weapons. They fire like guns but there is no repeating action so you have to be accurate.
There is also a time slowing element called a "stasis field" which slows down whatever it hits when you fire it. These can be used to solve puzzles and slow down your enemies.
Your weapons, suit and stasis are all upgradeable, giving you choices on how you would like to customize your items.
All in all, the gameplay works very well for what it's suited for. You certainly don't feel like Master Chief, jumping everywhere and beating people to death. But I think this adds to the mayhem, like in your worst dreams when you're running away from something and it feels like you've got sand for feet.
Audio/Video
The ambient sounds in this game are unreal; sounds of your enemy's footsteps in the distance, dripping water, the echoes, the lonely sound of your own footsteps...it's all very creepy and very well done.
Regarding the graphics, I'm playing on a 46" 1080p Plasma.
The graphics are also very well done, the USG Ishimura has all the trappings of a Hollywood backed set with the subtleties of an Aliens-esque atmosphere, of a battle that was lost...
Final Thoughts
If you like a great (and not too badly written) Sci-Fi Survival Horror game, get this one. It's a really good looking game with some (so far) memorable moments and new ideas...it's also pretty good in the horror category.
I'm going to seem like a total fanboy but...
Story 10/10
Gameplay 9/10
Graphics 10/10
Audio 10/10
Overall 39/40