Another fun fact: the instruments, tempo, and structure of Mania's version of "Satan's battle theme" are exactly the same as Eggman's boss theme (Ruby Delusions).
They even stem from the same project file! (Boss theme came first). They're entirely interchangeable 😄
The boss battle theme for Chemical Plant in Sonic Mania is taken from the 2 player mode theme from Dr. Robotnik's Mean Bean Machine, which in itself is pulled from Satan's battle theme, "Final of Puyo Puyo", from Puyo Puyo for the Mega Drive.