Ultimately, it's a familiar idea executed well with several personal annoyances. I'm still at a loss as to why so many modern indies need to look so damn "kill yourself" desaturated in color. This isn't the worst offender and much of the runtime is spent under the sterile lighting of a gas station convenience store, but it's still enough to make the whole film a muted eyesore.
The other aspect that grates the nerves is the frantic Bourne series editing style applied to the action sequences. No, the monster doesn't need to be nakedly seen like the laughable Rawhead Rex, but the camera man always looks in mid-banana-peel-trip in the millisecond "flash" edits as the thing (*hint hint*) lurches and our protagonists run for cover. The viewer can barely get a sense of what's going on or the geography of the settings during these frenzied endurance tests.
Though aside from these quibbles, this is a slice above the other recents I've seen...errr...recently. I'd give it a 6.5/10, but I can't give in to herald this as "incredible" or "amazing" like some reviews I'm sampling. If anything, this film will remind you to plan a revisit to Carpenter's The Thing or The Raft sequence in Creepshow 2. Magnolia's DVD transfer is solid for a single layer disc treatment, but there's two very faint digitally offset lines throughout the entire film. Not terribly noticeable, though A/V dorks like myself are likely to spot it.