X-Men: Mojo World Cheats
for Game Gear

Unlimited flight

Enable Mutant Power with Storm or Rogue then push Jump to begin flying. Hold Attack while in the air and disable Mutant Power. This will allow your character to fly without diminishing Mutant Power level.

Defeat Fitzroy

When you see the red bar on Fitzroy's chest, duck and fire your Mutant Power. His shots will fly over your head, but your shots should hit him.