At the ‘Bonus Content’ menu select the ‘Enter Code’ option and input the following codes at the ‘Secret Cheat’ screen to activate the corresponding effect in the game.

Unlock ALL Combos:
Enter Swampfire, Gwen, Kevin, Ben.

Invincibility:
Enter Kevin, Big Chill, Swampfire, Kevin.

Unlock Level Lord:
Enter Gwen, Kevin, Big Chill, Gwen.

Unlock Infinite Aliens:
Enter Ben, Swampfire, Gwen, Big Chill.

Unlock Goop:
Enter Ben, Swampfire, Kevin, Big chill.