Restarting Game:
To restart the game from the controller, press A + B + Z + Start at the same time from anywhere in the game. This is good for when you know your screwed and you don't want to get up (we gamers are so lazy).

Sound Test:
Start a new game and enter MUSIC_ON as a case-sensitive name.

Delete Saved Game Files:
Start a new game and enter DEL_DATA as a case-sensitive name.

Thanks to Revolution reader ike!