It's still very much worth playing, however. The actual GAMEPLAY is really solid.
It feels like a mix of Resident Evil 4 and Doom 3 with its own unique spin on certain things. The environments are more varied and interesting than Doom 3, I should note, and the gunplay is satisfying in an RE4-like manner (though the controls are superior in Dead Space).
I suppose, aside from the lack of horror, the sound is the other letdown for me. As noted above, I believe it is technically well done, but it lacks a unique personality. That's not to say games like RE4 or Doom 3 did it any better, though (Dead Space sounds better than either of them). It's just that, a unique sound design can really create a special atmosphere. For instance, the film "Sunshine" was given such a unique flavor by its audio design. It presented a similar type of environment, but it felt original as a result of the audio. Same deal with many of the other horror games I mentioned above.