I quite enjoyed Donnie Darko and I've always been confused by people who said it didn't make sense, since to me it's always been a movie about the uncertainty of the universe. Living in our familiar environment on earth, we're lulled into thinking the world is stable and predictable but really, we have a blinkered view of the universe and what's out there, how things really work is weird and unknowable and if Donnie doesn't understand it, or the viewer doesn't understand it, it's because it's not meant to be understood and if we're lucky we'll catch a glimpse of it before we're crushed by a jet engine or a guy in a bunny suit runs over your girlfriend, and to demonstrate this the movie develops a bunch of sympathetic characters and kills them all. That's what I got out of it, at least.

I find the opinion that the movie's a pretentious turd to be more understandable, though personally I think that's more a problem with certain fans because I don't remember the movie itself being particularly pretentious.