Unlimited lives:
Go to Dracula's castle after getting the Bubble gum blaster in Duckberg. Find the first stack of large barrels. Get the extra life from the last barrel on the second row. Leave and re-enter the castle to get the same extra life.

Pepper madness:
Pause game play after Donald eats a pepper. Press Up(4), Down and resume game play.

Hint: Maze level:
Follow 1, 5, 4, 4, 2, 6 in the maze level to reach the tiger.