S. Darko is one of many sequels that has no reason to have been created at all. But even if one puts the original film out-of-mind, and only look at the sequel on it's own merits, the movie still falls completely flat.
The film picks up 7 years after the original left off, Samantha Darko and her friend Corey are on a cross-country trip heading for Los Angeles. When car problems leave them stuck in a little town by the name of Conejo Springs (which is populated by a community of horribly written character's), the girls are forced to mingle with the townies, and Corey finds herself at home with the boozy losers, while Samantha, still in pain over the death of her brother (Donnie), finds herself drawn to the Outsider by the name of Iraq Jack, a disturbed Gulf War vet who has learned through bizarre visions that the world is coming to an end on July 4th, 1995.
It seems that Nathan Atkins is a fan of Richard Kelly's work (including Southland Tales because the character of Iraq Jack seems similar to the character 'Pilot Abilene' & the end of the world date being on 'July 4th') But Atkins can't write believable dialogue to save his life. And the director 'Chris Fisher' doesn't seem to understand what made the original film so good, which was the feeling of being able to connect with the characters going through something this crazy. And if the audience doesn't care about the characters on-screen it becomes very hard for them to feel any effect of the narrative structure.
S. Darko is a hollow cash-grab by producers who must have never understood what Kelly was going for, but they now control the rights to the Darko universe, and they're hoping to collect any profit from this wannabe Donnie Darko replica.