Great! The story is very interesting and was well-conveyed - it didn't seem pasted together if you know what I mean. The music at one point has a really interesting ear-static effect. It sounds very similar to bubbling foam in your ear (like that earwax removal liquid when poured in your ears). The music wasn't really my cup of tea but that effect was interesting. I had a lot of fun with this, and I actually was able to solve all of the challenges except for the riddle one (and the secret ending; I also looked up a word).
I usually have trouble with riddles and puzzles because I seem to miss the obvious answer and over-analyze it (or maybe my mind works differently from the authors'). I'm still kicking myself over missing the answer to the riddle challenge, but all the answers made perfect sense. Oh, and thanks for adding that bit about the, err, ungrammatical foreign language there (trying not to spoil it here). That was a thoughtful touch, because it would've bugged me otherwise. :D
I look forward to a sequel sometime in the future.