A lot of things have already been said about Dead Space -- verbs and nouns, mostly, with adjectives being the most common, as well as the most defining. Adjectives like unoriginal.
Dead Space is not an original game. It included slowing-time and kinesis gimmicks -- both in vogue at the time of Dead Space's release. It also included thrills and shocks found in any Resident Evil or Silent Hill game of the last ten years, or so. Science-fiction, space, poor lighting, over-the-shoulder shooting; all things that have come before. That said, Dead Space does all these things better than almost all of its contemporaries. Everything is polished to such a shine that casts a dramatic glare over its unoriginality.
Now that's out of the way we're free to talk about the new things that Dead Space brings to the table.
Let's start with the HUD. Dead Space lifts its life bar out of the corner and plants it firmly up the spine of it protagonist Isaac. Menu's hang in the air in front of Isaac's face and he must interact with them in real-time.
There are also some very cinematic scenes where Isaac's dragged by his feet and forced to take aim with a character-centered, 2nd person aiming scheme. In other words, aiming up moves the laser sight up over Isaac's head, down aims down towards Isaac's feet, right aims right, and left aims left. But, Isaac may be upside down, or turned and which way of sideways at the time. Disoriented, he must put down his enemy before very, very bad things happen to him.
So, Dead Space may not be the most original game, but it is a damn fine one.