Surprisingly good! I'd seen the bulk of it before in one of those "every scene the monster is in" videos on Youtube, but that understandably left me with some holes in the plot. This is purely a body horror movie, and it does it REALLY well; I honestly wish there were some steadier shots of the "monster" later on so I could appreciate the details more. The plan near the end is pretty dumb, though [spoiler](with lowering Seth's body temperature so the monster couldn't detect him; just do the original idea with the fire and wait for the thing to run into it, or craft a rudimentary flamethrower!)[/spoiler], and the last twenty minutes or so suffer heavily from shaky cam, which I deducted stars for. Also IMO the [spoiler]final shot of the dead animal full of splinters wasn't necessary to show that the thing wasn't totally gone; dead animals upset me, especially if there are indications that they probably died horrifically and in pain. They could've just shown a patch of the splinters on the pavement where the animal had been, seeing it initially was more than enough for me.[/spoiler]

[spoiler]I also averted my eyes for the part where they cut Dennis's arm off, for obvious reasons. Imagining having to do that is bad enough, but it being done with a box cutter's short little blade made it worse.[/spoiler]