Only one problem I've found with my game: The music plays 100% fine at the title screen and all levels up to 17 then it goes screwy. There must be some memory overwrite from MPAGD on level 18. But, I've tried putting the music and player at: $e000, $6000, $d200 and it happens with every location. Reach level 18.. music scrambles.
Also if you have MPAGD v0.7.9 or later the build.bat file will delete user.asm so remove that line from the build file.