I think what if we have "Game B - R.O.B. the Robot%", we may have "Game B - Phases 1-25" and "Game B - Coop". Rules:

(Game B - Phases 1-25:
Timing starts when you press start on Game B
Timing ends when the end of level music starts after completing Phase 25.
One player must use Controller 2
Everdirve or PowerPak may be used.)

(Game B - Coop:
Timing starts when you press start on Game B
Timing ends when the end of level music starts after completing Phase 25.
Two players must use Controller 2; First player control blue pipes, second player control red pipes
Everdirve or PowerPak may be used.)