On level 3-5, Leap of Faith, jump on the first platform with arrows on it, and when it drops, you will land on another platform below you. It will teleport you to another part of the level. You will find four smash boxes. Smash them to get four extra lives. Repeat this prosess until you have all the lives you need.
Enter the password: Up, Left, Down, Left, Right, Left, Down, Up, Left, Right, Right, Down, Right, Right, Up