As others have said this is kind "Revenge of the Nerds" meets "Night of the Living Dead". It's also kind of sweet and romantic in a way. It kind of reminded me of Bob Balaban's underrated horror/comedy "My Boyfriend's Back" released about ten years ago or "Idle Hands" a little more recently. After participating in a hilariously screwed-up graveyard ritual with some half-assed satanists, three nerdy losers are killed in car accident (which results from a hilarious bong-related mishap), and come back to life as zombies. They decide to use their undead abilities to get revenge on their enemies and chase after the girls of their dreams.
To this movie's credit it's very funny, and all the characters, especially the three protagonists, are well-drawn and likable. There's also some subtle jokes like the characters attending "Friedrich Nietzsche High School" (which actually might not be a joke in Germany) and the homosexual gym teacher named "Mr. Stalin". The downside though is it's a little too much like a modern-day American teen movie (which makes it pretty ironic that Hollywood is apparently going to remake this). The teens are ridiculously horny even by teenage standards and there is no end to the gross-out, sexually related humor, yet there is also very little (female) nudity. The main protagonist is in love with an icy Aryan blonde, but in typical Hollywood teen movie fashion doesn't seem to notice that the "goth" girl-next-door who taught him how to kiss is absolutely gorgeous. I also wish it were even more "politically incorrect"--the funniest scenes are the ones Hollywood would have been too leery to put in a teen movie, like the irresponsible dope smoking while driving or the scene where the dim-witted satanists accidentally draw a Star of David instead of a pentagram ("The only thing you're going to summon with that is the Jewish Council!").
If you are going to watch a modern-day teenage movie though, you could certainly do worse than this (a lot worse).