Mario's Time Machine

Debug menu:
Press B, Y, B, Y, B, A, B, Y before the copyright screen disappears to display the "Debug" menu, with options for a museum selector and a sound test.

View ending sequences:
Press Y, A, B(2), A(2) at the title screen. The sound of a coin will confirm correct code entry. Hold X + A to view the good ending, X to view the normal ending, or any other button to view the bad ending.

Level passwords:

Glitch: Remove bad marks:
If you have two sad faces on your notebook, go to an answer that you already completed and put it in again. You will go back to having no marks against you. This makes it easy to guess random answers to your questions.