Very cool! I love the ambience and the mood, and the way you've integrated the puzzle element as part of a story-telling device is brilliant. I'll admit I had to use the walkthrough extensively, but I just had to see the ending and evidently I'm terrible at this sort of thing :)!
The ending caught me off guard too. I won't spoil it, but when I saw the shape I thought he had built a set of stairs to walk over the girl (thus learning his lesson to stop pursuing her). Your ending certainly goes in a different direction!
Great job, man!