The Butterfly Effect: Director’s Cut (2004)

The title refers to the principle that if you change one thing, everything that follows is also changed. It’s happening all around you, even now while you read this. If you could undo a traumatic event in your past what would it change about your present? Would it make you a better person?
It's a plot device almost as old as sci-fi itself, so the film distinguishes itself from what’s gone before by adding some heavy adult themes and upping the severity of the consequences.

NOTE: Score applies to the Dir. Cut, which has a more emotionally powerful ending than the theatrical version.

3 nonlinear systems out of 5