Run up to the witch cat. She will begin shooting stars. Dodge them and let them hit the ground, causing skeleton cats to spawn. Kill three of these cats, might need to be near witch to work, then key will spawn in front of witch. Get kid in upper lefthand corner, then get to kid's ghost. This will cause the ghost cats to despawn. The witch will begin flying around. Using the roll, you can attack her. Do this until end screen shows up. Congradulations!