What Does The Ending Of Donnie Darko Really Mean?

There's another, more troubling interpretation to be had, though: that Donnie is left trapped between heaven and hell for the sin of murder, while Frank takes on the role of the devil; that this is not a Garden of Eden, but purgatory.

Donnie Darko begins with the character waking as if he's been literally dropped back into the world, and ends with him watching the plane carrying his mother and sister plummeting to the Earth, before entering a 'portal' and being taken back to square one. This film is obviously set inside a loop, so what if this has all happened before already?

Anyone who's seen the episode of The Twilight Zone - clearly an influence on Kelly, seeing as one episode inspired The Box - in which a U-Boat commander is forced to constantly relive one punishing day as retribution for his crimes, will see a familiar pattern in Darko. Perhaps Donnie, like Twilight Zone's U-Boat captain, is stuck in purgatory, forced to live his last days over and again, haunted by the man he killed and made to repeatedly watch his loved ones suffer.

It could be said that Donnie's sacrifice at the end, then, is what saves him from eternal punishment - here, he allows himself to die so that his family may live, and so he may finally exit purgatory into the afterlife.