View the credits at beginning of the game.
Save Daredevil and get the DD tokens at first level.
Have 5 lifes.
Defeat Dragonman. (Normal or Hard)
Finish level 1.
Do the Debug Menu code.
Defeat The Eel. (Normal or Hard)
Finish level 2.
Finish level 3.
Finish level 4.
Defeat Thermite. (Normal or Hard)
Finish level 5.
Defeat Blitz. (Normal or Hard)
Defeat Super-Adaptoid. (Normal or Hard)
Finish level 6.
Finish the game on Easy difficulty.
Finish the game on Normal difficulty.
Finish the game on Hard difficulty.