No Time Man nor Oil Man because they weren't in the original game so I excluded them.

Mega Man 7 & 8 sprites based on Rockman 7 & 8 FC.
Mega Man 11 sprites based on: https://www.deviantart.com/peggdraws/...

Music used:
Mega Man Powered Up - Boss Theme
Mega Man 2 - Boss Theme
Mega Man 3 - Boss Remixed
Rockman 4, 5, 6 Complete Works - Boss
Mega Man 7, 8, 9 - Boss Theme
Mega Man 10 - Boss Arranged
Mega Man 11 - Boss Theme