The original "Dead Space" was a great blend of survival horror, puzzle-solving and action. Sure, it got a little redundant after the whole monster-jumping-out-of-the-vent technique was used for seventh time, but really, there wasn't too much to complain about. Apart from adding multiplayer, "Dead Space 2" is really all about polishing the basic gameplay of the original. Fully 3D zero grav maneuverability, more action sequences, better graphics, that sort of thing.
Even if it won't be reinventing the wheel, I can't help but be impressed every time I've seen the game. The first time was at this year's E3, which featured some slow, scary parts, some brain-churning puzzles and some very fast, holy-crap-how-am-I-still-alive parts. Even though it was a demo, the pacing felt just right.
But you don't have to take my word for it. EA will be releasing a demo for "Dead Space 2" on December 21 for Xbox Live and PSN. It's actually the exact same demo that was shown at E3. Bad news for me, since I already played it, but good news for you!
Presuming it is the exact same demo as was shown during E3, you can expect it to run around 10-15 minutes, depending on your ability/inability to solve puzzles in zero gravity. You'll also be able to try out one of the game's new weapons: the Javelin gun. Guess what? It shoots javelins! I didn't find it quite as useful as the line gun, but for large, slow-moving enemies, it seemed to do the trick, pinning them to the wall with plenty of satisfying viscera.
Even if you didn't totally love the original "Dead Space," it's worth giving the demo a look. I think the developers are doing some pretty impressive things with interactive cutscenes, basically blowing the "God of War" button-based quick time events out of the water. Plus it's free.