Mickey Mania (SNES)

Hidden room:
Jump on the cat next to the cabin in level 1. Then, follow the cat down the hole that it jumps into.

Level select:
Enter the sound test menu. Set the music option to "Beanstalk1". Set the SFX option to "Extra Try". Highlight the "Exit" option and hold L. A sound will confirm correct code entry. A level selection screen will appear after starting a new game.