Well you're in luck! Dead Space 2 has a Demo, and it's available right NOW on XBL, and PSN!
If you've never played Dead Space, it's either because you've never heard of it, or because you were too scared to continue playing it. I joke not, people refuse to finish this game because it's "too scarry". Naturally I love it. One of the best horror games I've played in a long time.
Play the demo guys and gals. Go to your consoles and download the demo. You don't even need to play the first one to enjoy this second one (although I do recommend it). This video that was just debuted yesterday will help catch you up on the story.
I hope this one is just as good as the first, or better!
EDIT: Added demo video.