I played your demo. First off, I would recommend you keep all of the music files that won't be used in the game in a separate folder, as it was hell to download. As for the game itself...
I thought it was really enjoyable. The music choices were very good. Most of the mapping was very well done. I did, however, feel that your word choice and grammar needed a lot of work. Some of the aspects of the game were lost in translation for me. I didn't understand how the elevator worked, although it was kinda cool, or anything about the tunnel. There are just little things here and there that bog it down. Otherwise, it was nice. I can see that you've done a lot of work.