When you are in the "password entry" screen, you can enter these "please" codes to reach the corresponding levels.

Password - Effect

PLEASEHH - City of Forever
PLEASEKK - Deep City
PLEASEOO - Final Fight
PLEASEEE - Ice Zone
PLEASEFF - Island Zone
PLEASEUU - Marble Sea
PLEASEWW - Open Ocean
PLEASEQQ - Origin Beach
PLEASEGG - Pteranadon Pond
PLEASEZZ - Ridge Water
PLEASEII - Undercaves