On one hand this makes up for the recent remakes of APRIL FOOL'S DAY and DAY OF THE DEAD. On the other hand it's unnecessary, especially with a PG-13 rating.
The direction, script and actors are good and there's enough characterization so that you actually don't want them to die. It's also very linear, clearly establishing why this psycho is obsessed with this young woman and why he crashes her senior prom. The psycho kills everyone because that's the thing he does and actor Johnathon Schaech's performance is one of the best things about the film.
The killings, while brutal and intense, are primarily off screen and everyone is killed the same way, with a wicked looking knife. There's also the role of the athletics teacher, which would have been a great cameo for Jamie Lee Curtis.