At the title screen, open the "PASSWORD" option and you'll be allowed to enter these passwords; once entered, press the Start Button to use it. However, it seems that passwords for the final three stages will only work if the "RDEST" password is first inputted. When actually playing, take note that some of the passwords the game gives for Stages 4-2, 4-3, and 4-4 are either glitched or fake, giving you "_1INYFOR", which will not work.

Effect	Password
Stage 1-2	BOOME
Stage 1-3	RANDH
Stage 1-4	ISCHI
Stage 2-1	LDREN
Stage 2-2	MUSTR
Stage 2-3	EACHT
Stage 2-4	HESAC
Stage 3-1	REDAL
Stage 3-2	TARTO
Stage 3-3	FULFI
Stage 3-4	LLTHEI
Stage 4-1	RDEST
Stage 4-2 (enter "RDEST" beforehand)	INYFOR
Stage 4-3 (enter "RDEST" beforehand)	ASMIK
Stage 4-4 (enter "RDEST" beforehand)	WORLD