I came up with what seemed to me like a fun challenge, figured I'd share it here in case anyone else wants to give it a try.
The challenge: Battle all 29 solo villains in the video game and all 5 members of the Vengeful 5 using each variant exactly twice. Each environment must be used at least once and no more than twice. Games may be played in any order.
The objective: Win all 30 games! Failing that see how close you can get.
Good luck saving the multiverse!
