Secret passwords:
At the title screen, press B to enter the password screen, now input one of these passwords to access the desired level. The passwords are given to you after completing the corresponding stage, so they aren't secret actually, but there is no password systems in any other versions of the game.
TRF - Stage 2
GZB - Stage 3
PKW - Stage 4
HQJ - Stage 5
BLV - Stage 6
WPT - Stage 7
RPR - Stage 8
