High school film noir.
Nugget: super-stylish homage to a genre re-enlivened by the shift in setting.
Please go to FilmExposed for the full review.
I should add that since seeing this film I've realized that my criticisms of the ending are a little ignorant and unfounded. It's a convention of the film noir genre to recount the plot, explaining what you've just seen, so to complain about this is unjustified. My bad.
[Update: Friday 17 June 2011: looks like FilmExposed is no more, so that link is broken.]