one audience perspective **CONTAINS SPOILERS***

I was impressed what had been achieved, and the convincing acting.
The title is wrong, it leads me to expect a quirky comedy about mistaken identity. The off-screen character of Harry doesn't make an impression, and what's more his name isn't necessarily evocative of what he had done (it's not scary and kind of sounds "made-up").
The most unsatisfying aspect of the movie is the story itself, especially after the surprise twist ending is revealed. It turns out the writer's book agent, (a peripheral character) paid $30,000 to an ex prison buddy who is working as tramping guide to randomly kill a tour party member in the hope of inspiring the author to write more books about murder so that the agent, would make more money to get himself out of debt. This is an illogical investment plan. A lot of time would have to be spent making two characters that I would be able to believe capable of colluding in such a crazy scheme. As it stands in the film, it is a contrivance of the most baffling kind. To be honest, it undoes the viewing experience.
I found the film effective from moment to moment, but the overall shape of it, it's reason for being, frustrates me. I wish this film-maker had found or made a decent story to display his passion and obvious talents.