My simplified take on what happened

Rating: Null/10 (12 August 2009)

I saw the original version of DONNIE DARKO and enjoyed the air of mysteriousness. However, after finishing the film I still didn't quite grasp what was going on. After reading through countless explanations and discussions on the topic, this is the simplest way I can make sense of it all:
***SPOILERS!***
Due to some clerical error (caused by God, time-traveling aliens, who knows?) a jet engine was sent 28 days back in time, falling onto the Darko house with no explanation. This was not supposed to happen. The engine didn't belong in the past.
What this did was create an unstable universe. In 28 days, when the jet made its flight, the universe would have two identical jet engines existing simultaneously. This would upset the time-space continuum and cause the universe to collapse upon itself.
Donnie Darko was enlisted to save the universe. He had to make sure the jet engine in 28 days was sent back in time, thus resolving the time-space error.
(Think about this: in the life-cycle of the jet engine, it was built, it flew around a few times, on Oct. 30 it broke off and landed on Oct. 2, where it was retrieved. If Donnie hadn't sent it back in time, the engine would've stayed in Oct. 30 and Oct. 31, while the same engine also existed from crashing on Oct. 2. The one engine would become two duplicate engines for no reason. To keep one engine in the "life cycle", the Oct. 30 engine had to be sent back in time to become the Oct. 2 engine. Confusing, I know...)
Once the jet engine is sent back in time, the universe re-sets from the night the engine crashes. Everything that happened in the 28 days in the unstable universe is wiped away. The universe is stable now because the jet engine has a reason for appearing out of nowhere. That reason is because someone (Donnie) sent it from an alternate timeline. (Before it was just a sloppy goof by some 4th dimensional power, manipulating time-space.)
Donnie didn't have to die to save the world, but saving the world likely meant that he would die. (Since the engine crashed into his bedroom.) Donnie was willing to make that sacrifice in order to save the world and to "save" Gretchen.
Frank the bunny is kind of a time-traveling ghost. He's killed by Donnie on Oct. 29, but his ghost goes into the past to guide Donnie on his way.
Why was Donnie chosen? Perhaps because he would've been killed in the accident, so he was easy to convince that the universe needed saving. If Donnie had died, maybe they'd have to find someone else to send the jet engine back in time. Or maybe there was something special about Donnie, and he needed to be saved in order for him to right the universe.
But in the end, the engine crashes into Donnie's room on Oct. 2. Donnie is killed. Everything from the 28-day alternate timeline seems like déjà-vu. And an unexplainable jet engine is retrieved for further analysis. (Nobody knows what to make of it, but we know it came from another reality.)
***END OF SPOILERS***
It's still complicated. The Director's Cut supposedly dives much deeper (too deep?) into the sci-fi mythology behind everything. But I think I like the artistry of the original version better. The viewer isn't sure what's going on, even at the end. Is it real? Is he just crazy? What will happen in 28 days? It leaves some things open to interpretation.
But I think DONNIE DARKO, in its original form, is a film with almost no answers. The ONLY way for anyone to know what director Richard Kelly was going for is to do research and read interviews, listen to commentaries, dive into the website, watch the Director's Cut, etc. I don't think you can make sense of the movie without an explanation from the filmmakers.
The Director's Cut spells everything out, but the film becomes more of a crazy sci-fi flick than a dark mystery. Personally I prefer the original.
Donnie Darko is a troubled teenager. He starts getting warnings about the end of the world and believes that he alone has the ability to prevent it. Influenced by an imaginary friend, Donnie's actions become destructive. Meanwhile he meets a girl, goes to therapy, and tries to unlock the mysteries of time travel.
The movie is very complicated, and is clearly designed to be so. It's full of layers, from the psychological angle to the Christ-like symbolism. It's one of those movies with dozens of interpretations. A movie that allows people to see what they want to see. Often over-analyzed and possibly over-rated.
I think it's a very interesting film, capturing a sense of mystery with storytelling artistry. The film might not "make sense", but you can tell that it was crafted that way deliberately. The acting is very good and the movie sticks with you days later. I wouldn't call DONNIE DARKO the "greatest movie ever", like some people, but it certainly is an interesting film.