The definition of an independent film has long been argued over. Being independent of a studio might be one definition but is any art made in a vacuum of independence? Taking the generally accepted definition of independence in film - one that is created outside of the major studios - no film seems to have had more impact on modern indie soundtracks than the era-defining Donnie Darko.

A cult sleeper hit in every sense, word of mouth reviews helped UK screenings to sell a ton of tickets as well as bucketloads of DVD and VHS copies. The constant chatter around the film's complex plot and stylised aesthetic led to the film featuring in many internet lists involving the phrase "To see before you die." It's tailor-made for millennials, which is no bad thing, even though it now finds itself alongside the likes of Inception, Lord of the Rings and Batman vs. Spiderman vs. Superman 7 as one of the best films of all time (according to those lists).

Set in 1988, Donnie Darko was released into a panicked, post 9/11 world where nostalgia meant more than ever. The drunken, almost-Lynchian suburbia which Donnie exists in was under threat - not that the director would have known. It's strangely fitting that for a movie which confuses so many with its unpredictability, that an unpredicted event should affect the mood in which the film would first be received in. We never really know what's going on but that's life.

For an independent film, director Richard Kelly and composer Michael Andrews managed to get the rights to some pretty brilliant pop songs. There were sticking points, but these sticking points turned out to be huge strokes of luck. Let's start with the iconic opening scene of Jake Gyllenhaal riding a bike down the sloping hills into the Middlesex, Virginia suburbs to Echo and The Bunnymen's 'The Killing Moon':

The opener was supposed to be INXS 'Never Tear Us Apart' (it was used in the director's cut of the film, but was later substituted for Echo and The Bunnymen's magnum opus. And who can argue about the perfect match between the band name and a film obsessed with rabbits?

It's tough to choose which of Donnie Darko's scenes has the best music but there are few cinema soundtrack moments in my memory which have the pure impact as the school intro soundtracked by Tears For Fears 'Head Over Heels':

Bouncing off the bus and into the school, the camera pans from the geeks to the bullies to Sparkle Motion in a perfectly executed scene which says so much through the music. All the '80s OTT glam and school days nostalgia of the scene works brilliantly because it's not relied on as a crutch to base every scene. Take the party scene, Joy Division's 'Love Will Tear Us Apart' plays in the background and foreshadows Donnie's death. Same great music choice but totally different tone.

All in all, there were three song swaps which have been disclosed, apart from INXS/Echo and The Bunnymen - Sparkle Motion's canonical performance to Duran Duran's 'Notorious' was originally slated to be 'West End Girls' by the Pet Shop Boys. Again, not many people would argue the final song choice was a bad one.

Quite possibly the biggest stroke of luck was missing out on U2's 'MLK' and replacing it with a sombre and stripped back cover of Tears For Fears 'Mad World'. The film's composer Michael Andrews enlisted his childhood friend Gary Jules to sing the vocals to his piano arrangement of the track. Another last minute change, due to a situation which was out of the hands of the studios. A perfect example of the nature of independent film and the circumstances which can lead to an accidental masterstroke. It makes you wonder how many second choices would have been a better idea... could (and should) Apocalypse Now's 'The End' have actually been 'Dancing Queen'?