From my perspective as a sound guy...
I didn't like the wall-to-wall music. I would have opened with late fall sounds (although it doesn't look like that, but the bad guy is filling his freezer for the winter) - some birds, rustling leaves, migrating geese (maybe the geese wake him up?).
Good solid Foley and sound effects are needed. Most notably missing - the running footsteps; big, solid, "meaty" hatchet sounds; being dragged and grabbing at the dirt.
The dialog needs to be smoothed out a bit (the production sound wasn't too bad, by the way). Since there is so little dialog I may have "tuned down" the bad guys voice to make him a little more menacing.
The music is too "monotone" throughout, it needs to change emotions more; some suspense music starts when he realizes there's blood on his hands, relief when someone appears to "help", suspense as the "help" becomes a threat, the chase, etc.
And I hate to be cliché, but, some transitional sounds to and from the flashbacks.
Not my area of expertise, but...
The blood looked fake, no blood splatter on his shirt and too concentrated on his hand and one side of the face. When he put his hand to his face no blood appears on his glasses.
In the "flashback" I would have had, say, a girlfriend who needs him to stop the truck so she can pee. That gives the "missing" person for him to have killed; in the "flashback" he hears her scream, he goes running to her, a heavy clonk on the head and a body fall as it all goes black.
Why would he suddenly believe he killed someone?
