Enter the following codes at the Title screen to unlock the corresponding effect. Hold down the 'B' button whilst entering the codes and if entered correctly Flash will yell as confirmation.

Unlock ALL Lives:
Up, Down, Up, Up, Down, Down, Up, Down, Select.

Unlock ALL Heroes:
Up, Down, Left, Right, Right, Left, Down, Up, Select.

Unlock ALL Powers:
Down, Down, Down, Down, Left, Right, Up, Down, Select.

Flash is Larger:
Left, Up, Right, Down, Left, Up, Right, Down, Select.

Flash is Smaller
Down, Down, Down, Left, Up, Up, Up, Right, Select.

Bad Guys are Bigger:
Up, Up, Down, Down, Left, Right, Left, Right, Select.

Bad Guys are Smaller:
Down, Down, Up, Up, Right, Left, Right, Left, Select.