Nice game. I had a GameBoy color but unfortunatly I don't have a cartridge to play your game on the console...
Like to see some real game for retro consoles.
Related to the gameplay, I didn't read the description it was a rythm game, despite that in the first run I already realized the relation of the spawning and music. Cool mechanic that helps to predict when the bullets will be spawned more or less.
Good work!