Very good game, not "for a sequel", just a great game in general. Just as much if not more suspense than Dead Space (1), mixed with an awesome continuing storyline and cinematics, cool upgradeable weapons and suits, crazy monsters, everything you could ask for! Would definitely recommend.
The Limited Edition gets you an extra game, Dead Space: Extraction, which is kind of a prologue to Dead Space, and it's designed for the Playstation Move, though you can also use it with just the controller. It's not particularly awesome, but it's a cool little extra Dead Space experience!