Simple but interesting premise. What if you could get your secret crush to love you back? The girl who played Nikki (Inde Navarrette) really gets to sink her teeth into it. The movie depends on her being good in her role and she is.
I know it's a horror movie requiring substantial suspension of belief, but a lot of the guy's behavior stretched the bounds of plausibility for me. It's one thing to stick around when she's just acting a little weird, but some of the things she starts doing while he just overlooks it makes you go, no, no one in their right mind would hang around with her at that point, even if she was his longtime crush.
Still it worked a lot better than the vast majority of horror movies out there, including more comic moments than you typically see, and it managed to create the overall effect of uneasiness for more less the whole movie. So it has to be considered a success (and a good time for fans of the genre).