Mr Do!

256 lives - If an apple appears in the top two rows, dig a tunnel underneath it, from the bottom up. Leave just enough dirt under it so it doesn’t fall. Then kill all the enemies except 1, and then lose all your extra lives. Wait under the apple until the last enemy closes in. Drop the apple, and kill the enemy before you’re squashed. The music will go haywire for a moment, and then you’ll be awarded 256 lives. Note- make sure you lose a life before spelling ‘EXTRA’ with 256 lives, or you’ll end up with 0!

Free game - Get the (hidden) diamond. Note- this trick works with all the Mr. Do games.