Most of the film is told from Steven's POV (there are only a few scenes in which he is not present) and we know that he is an unreliable narrator, so it is possible that the majority, if not all of the action, is taking place in his head -- that is he invents Percival as a way of concluding his search for Annie's killer, but then realizes that perhaps her death was punishment for his own violent actions.
shareThat's a possibility, absolutely. I think the afterlife idea accounts for more, and does so more neatly, but this is in no way ruled out.
"We gotta get outta here." "I know, I can't stand this music!"
There's also the "dying brain" explanation in which Steven got killed by the car too, and as his damaged brain is dying, he imagines himself to be a hit man seeking revenge, then purpose, and ultimately acceptance. I'm not proposing that explanation, but it can also account for much of the story.
shareYes, that's another interpretation that probably would be valid. I didn't really give it a whole lot of consideration while watching (because this is a device I don't like all that much), but it did occur to me too, and I think it'd be supportable.
"We gotta get outta here." "I know, I can't stand this music!"