Just saw, this is so cool! Interesting idea to play different tracks with different keys. Better concept than I had imagined :)
I'll have to get access to Windows somehow...
Thanks again! Do you have a Twitter or something?
This is my twitter: https://twitter.com/DeadlySnaker, I'll have to start using it more often. Anyway, I'm really glad that you like it. Originally I wanted to make the visuals more interactive as well but I was too worried about being over ambitious and never finishing it.
Also, Game Maker lets me make builds for Mac as well, so I'll give that a shot later and see if I can get it to work.
UPDATE: Seems the only way I can make Mac builds is with a Mac so no luck there.