>>11812356
Behold: AK's original 8 robot masters. Two were cut entirely, and 4 were redesigned. Only 3 of AK's original boss designs made it to the final game.

I thought as a kid it was quite genius, that with the 6 bosses and Rock and Roll, you had 8 "robot masters" which means Roll is just as important to the lore as anyone else, but it turns out that the number was cut from 8 to 6 for budget and time reasons.