First, have a Mega Mushroom in your touch circle. When you get to the final Boss (the Monty Mole in the tank), use the mushroom to turn into Mega Mario or Luigi. When the Monty Mole pops out of the tank, jump on it to make the tank explode. However, the key will not come out, time will stop, and you won’t be able to pause game play. The boss room will be empty. Note: You must restart the game.