I never played the first Dead Space. While I'm a big Sci-Fi fan, (Mass Effect(s), Knights of the Old Republic, etc.) I didn't really see how it was anything other than another Resident Evil meets Space shoot-the-zombies mash-up.
Am I wrong? Is there a plot?
Yeah, there's a plot. As far as video games go, it's a fairly sophisticated plot, with an overarching storyline that has to do with a populist religion which is based around an artifact discovered on a planet being mined by humans.
There's also a subplot that focuses on your character (Isaac Clarke - named after Isaac Asimov and Arthur C. Clarke) on a personal level, his girlfriend trapped on a transport ship (the main environment of the game) and your character's desire to rescue her after he received a cryptic and disturbing video message from her. You also see signs of his deteriorating sanity as the game progresses from dealing with almost nonstop stress and trauma.
And then there's a subplot which centers on your teammates (non-player characters) conflicting personalities and goals.
As far as gameplay goes, it's fun as all hell. Instead of going for headshots and other typical attack strategies, you disable your enemies first by dismembering them. And instead of conventional weapons, you use mining equipment for your armory. The first 'weapon' you get, for instance, is a plasma cutter which is used to chew through rock. Later you get a flamethrower and a tethered power saw.... stuff like that.
The environment is very creepy and scary. There were a few places that made me want to crap my pants. It's extremely gruesome, gory and eerie. Keep that in mind if there's any kids around.
It's one of the more well-done games that I've ever played, I'm looking forward to DS2 immensely.