Books: How to Win at Super NES Games - Super NES Games Secrets
Conquering SNES Games
At the title screen, press Up, Down, L, R, Select. If you've done the
trick correctly, you'll hear an explosion in the background. Now go
to the Options menu and choose Mystery Mode. You'll be able to play
the whole game from an overhead view.
To get the Boss Car, press L, R, Up at the title screen. You'll hear
a rumbling sound. Begin a normal game. When you reach the
boss, you'll be driving his car.