Sometimes I doubt your commitment to Sparkle Motion
Three notes: these thoughts are only my own speculations. Donnie Darko leaves many things open to the viewer's interpretation, and it's one of the few movies where I do not care to know the creator's intentions in producing the story we are watching. Secondly, as with any discussion of this movie, there are spoilers aplenty. Lastly, I've only seen this movie once, and it definitely bears repeat viewings. I'll update these thoughts upon subsequent viewings if necessary.
One of the most fascinating sub-plots in Donnie Darko, to me, is its damning condemnation of the educational system in the United States. At every turn, Donnie tries to gain knowledge that will help explain or justify his own personal situation, and at every turn, he is thwarted. The message is clear: conform, or else. He is punished by his teachers for asking dangerous questions. His own personal quest for order in his life is turned aside, sometimes gently, as when Professor Monnitoff during a discussion about metaphysics which turns religious in nature, softly tells Darko, "I am unable to continue this conversation." Monnitoff's regret is plain, yet his fear of losing his job is greater. At other times, Darko's need for knowledge is rebuffed much more strongly, such as when he confronts Jim Cunningham during a school assembly. Darko has the audacity to question Cunningham's motivational speaking methods in a school environment, and he is forcibly removed from the assembly by the school's administration.
Everywhere in the movie, true knowledge and open-mindedness in the school is denied, only to be replaced by false self-esteem. Donnie begins to react violently to this teaching method. He vandalizes the school. He burns Cunningham's house to the ground, thus exposing a 'kiddie porn dungeon'. Donnie, in anger, exposes the hypocrisy of a system that places narcissism (for that is where self-esteem without self-critical thinking skills leads, does it not?) above almost all else. This is beautfully portrayed when Sparkle Motion, a dance troupe of which Donnie's little sister is a member, wins a place on Star Search and it's apparent that many teachers at the school consider this grab for celebrity to be a pinnacle of educational achievement. Donnie, through his actions, exposes all the poisons that lurk in the mud, and hatches them out.
As the film progresses, his journey leads him to a point where he has (and more importantly, recognizes) the ability to choose to reverse his actions, and, in order to save the people that he loves the most deeply, sacrifice himself. But by doing so, by taking advantage of an effect-precedes-cause loophole that is either divine in nature or somehow takes advantage of the way the universe works, Darko chooses to die rather than expose these hypocrisies. By doing so, he saves at least three lives, at the expense of his own: his mother's, his little sister's, and his girlfriend, Gretchen.
And yet, the thought that occurred to me at the end of the film: I wondered if any sort of greater good was served. Many events did not occur due to Darko's ultimate choice. Cunningham's abomination goes undiscovered. Teacher Karen Pomeroy is not fired for her actions--actions which, in Darko's first trip through the month of October of 1988, were blamed for being the catalyst for the vandalism Darko perpetrates upon the school.
If, ultimately, the movie is about the choices we make, we as the viewers get to ponder the consequences of Darko's actions. If he chooses to live, some good is being served because he pries open the flaws and faults in our society, even though a lot of people die as a result. If he chooses to die, many people are saved ... but at what price? Are Darko's actions and decisions at the end of the film truly selfless, or the most selfish actions one can make, wasting a remarkable opportunity to truly effect change upon the universe? Did Donnie choose order over chaos, or vice versa?
It is up to the viewer to decide.