Here are some cheats and tips for the game Rival Turf.
Hidden level 4 warp:
Defeat at least thirty enemies. Locate the door on level 4
and press Up to jump to the end of the level to fight the
Boss.
Change characters name:
Complete the game and attain a high score. Enter CHRCONF
as a name to access a character configuration screen. The names
of all characters in the game may be edited. Press Start
to begin a game using the altered character names.