So, let's start with the obvious. This is a flawed film. It's a lack of skill draped over a very solid skeleton. That is to say, it's actually a very well-conceived premise, and it plays out extremely logically. Moreover, the actors are honestly quite competent. The lukewarm end result is basically ALL the director's fault.
The female protagonist, I think is really well cast just for being so average, both in looks and in temperament. She has a born victim energy about her, which is exactly what the role calls for. She's essentially about as uncrappy a person as you can get, and the moral is, of course there's going to be SOME nutcase who feels aggressed by her. I do agree that she could have produced a little more emotion and tension in some scenes, but that's really the director's fault for not pushing for it.
As to the nutcase, he serves as a great case in point for the TYPE of movie that this is, i.e. I thought his performance was fairly badly conceived, but the point is, it's still good enough to be worth criticizing. I think it was a huge miss trying to make him into this explosive bombastic character in the second half of the film. He did a great job at being subliminally creepy. They should have intensified that. It would have worked so much better. As it is, both sides to the character seem almost irreconsileable, like two separate characters. Is he a meek timid weirdo or is he an assertive forceful A. Hole? Make up your mind!
In the end, there's just enough that works in this film for it to be SOMETHING, but not enough for it to be something GREAT. For one, a fair amount of effort was put into establishing mood, and it's very clear what they were going for, but in terms of pacing, cinematography & camera angles, the director just simply lacked the skill to pull it off seamlessly.
The bar scene in particular really dragged on. Now, on one hand, you could say the drabness of it adds to the realism, but not a lot was said, or more specifically, expressed. They could have made a lot more out of what ended up being just a fairly dull conversation. "Yeah I like fixing up wrecks, I don't go for tacky new tinsel." Maybe throw in some flashback sequences; Use a few snappy camera angles: SOMETHING to give this line the weight that you clearly want it to have.
The ending is a little weird, sure. Almost anticlimactic, but it didn't really bother me. There are LEVELS of anticlimax. Some are the level of "what the hell did I waste my time on?" This one I think falls more into the sphere of mundane horror that brings you just a little more close to reality than you thought you'd be. THAT didn't bother me. What REALLY bothered me was the fading of night into day. It was done so clumsily towards the end, that this alone is just such a dumb and avoidable continuity error, that it almost ruins the whole thing for me. I suppose this film is worth watching from an academic point of view unless you just really really love independent horror.