V and I disagreed about how successfully Dominik Moll brings resolution to this excellent thriller. She cited comments in the director's interview that a collaborator had convinced him to up the body count, something she sensed as increasingly artificial as the climax unfolded. (A "handicapped ending" in her opinion.)
The trouble is I suspect that Moll is struggling to make Harry work on two levels. On one, he is the traditional invasive whacko, but on another, he is Michel's alter-ego, an externalisation of the more direct and drastic approach to life's roadblocks that the compromise-prone father-of-three unconsciously senses as his route to personal liberation. Harry is a kind of amoral guardian angel, who helpfully arrives on the scene to rid Michel of both the material and human barriers to his postponed self-fulfilment. If Harry had simply run off the road at end, these parallel readings would have come apart in my view. (Harry's girlfriend Plum also has to be understood as a kind of anti-Claire.)
The influences of Hitchcock and The Shining are evident, but Moll has brought some innovative touches to the pyscho genre too. I liked the way that Harry's persona seems to have lasting corruptive effects on Michel and Claire, and how towards the end, Michel appears able to reverse the flow of manipulation on him. There's also a telling moment in the Kubrick-esque pink-tiled bathroom where we appreciate that a small change in the timing of Claire's arrival in the doorway might have altered all the final outcomes.