Continue game play:
Press A or B within ten seconds of losing all energy.

Power-up:
Enter NTTMMNWLPPBDZ as a password.

Bonus lives:
Stop the game after dropping below two lives remaining to obtain a password. Replace the fifth character of the password to N, then resume the game using the modified password for three lives. Replace the fifth character of the password to J, then resume the game using the modified password for two lives.

Password Status
MQTRLZPBRDZZ Start with iron sword
RLTRLZPBMMZK Start with axe and helmet
WBTRLZPBDPZW Start with shield
PJTRTGHTGLNM Start with all armor
DDBMNWMBZZDJ Air level, cloud area
JJTRJZRZQMWN Water level
XXTRTDGXRPMH Water level, in the water
JBTRHMWQRRWW Water level, with Blightwater spell
NRTRZBDTRQDL Fire level
KJTNJWQXRLTP Fire level, with Fleetfoot spell
PLTRMBRLNBDR Icefire
WLTRMBRLNBKR Icefire, with seven-league boots
BDTRBTTNNGNT Final level