Heh. I see some people are fanatics of this cult classic.

Yeah Tifa, you've got the main idea down (which believe it or not, is hard for a lot of people to absorb). It's a sci-fi thriller but, as GooeyToast said, it's supposed to also represent a number of "ordinary" themes... the angst and insecurity of being a teenager, a first love... think about all the tiny subplots and nuances of the film, not to mention how complex Donnie's character is. This is a guy who can talk of the philosophy of time travel and switch to smurf genitalia the next. You have a crazy inspirational scam ringleader brainwashing a community (not uncommon), a clueless, worried set of parents, a psychologist, two liberal teachers fornicating, a fat asian chick... there is a large amount of "normal" other storytelling going on in the shadow of the great alternate dimension plot, adding to the depth and complexity of the movie. It's fantastic.