There's more than one side to every story.
John's character development was handled amazingly well. He had very little dialogue to work with, and yet he managed to show the audience dozens of hints about who he might be. No, I can't go into any detail about what sort of person he was. This is something best discovered by each new viewer on their own. The clues are there for anyone who pays attention to subtle things like how he speaks to the audience or what facial expressions he makes.
I'll admit to being confused by what was going on in this film for the first half of it, but that turned out to be the best possible thing I could be feeling at that moment. This is the sort of storytelling that requires a puzzled audience in order to get its point across because we don't know anything about who John is when we begin watching and the things he shares about his life don't quite seem to fit into a coherent picture of who this guy was before violent things began happening to him.
Speaking of the violence, this was definitely a horror flick from beginning to end. There was a psychological element to what John was going through, but the story had its fair share of gory elements as well. As with the other questions about who John was and why anyone would want to hurt him, the film left a lot up to the viewer's active participation and imagination. My interpretation of what was really going on could be wildly different from how someone else pieced together the same snapshots of this characters life. This was a good thing!
Anyone who loves horror or tales that can be interpreted multiple ways as much as I do should definitely give Ostinato a try.