Warioland 1

Start the game, enter any area and press Start to pause. Press Select 16 times to make a cursor appear on your number of lives. Then simultaneously hold A and B, and move the cursor box left or right. When you get the cursor over a number you wish to change, press Up or Down. If you put the cursor on the Wario face at the bottom left and un-pause, you'll get a better hat.

When playing, press START. Then press SELECT 16 times. When you see a flashing square on the last digit of your lives, press A and B and move the square to the number of coins and press up or down depending on how many coins you want.