Mr Frosty vs Popon - Kirby the Dream Battle

Mega Man and all bonus stages - Mega Man Robot Master Mayhem fan game

Eye of Agamotto and more

CPU CO-OP in Aventers United Battle Force

Power Stone Edward Falcon in all bonus stages

All Bosses - Pocket Dimensional Clash 2

Old Oak Tree from Castle of Illusion

New boss: Mr. Negative

I think I already saw this somewhere...

X-Men’s Iceman Takes on the Hydra