Going back to my Music GCSE, I'd describe the structure of this film as having a simple ternary form - A-B-A' - standing aptly in this case for Adult-Boy-Adult'.
The limitations of this 'song form' are plenty and frustrating for a viewer looking for a story - what happens between A and B, or more significantly, between B and A? Are we just looking here at a story of guilt? Are we supposed to draw a link between what happens in B as a way of explaining Joe's (CRAIG) behaviour in A? I'm not sure we're able to make such assumptions.
So instead I could only take each of the film's three sections as self-standing, but that doesn't mean that I didn't enjoy the film as a whole.
Indeed, a film that resists a coherent narrative and prevents identification with its characters is perfectly suitable structurally for such themes of guilt and escape.
That is what makes this film moving. Not for the on-screen emotion, but for what is left out, unseen and lost in the hyphens of the film's structure.