Hold A + B on controller two at the title screen and press Reset. Press A or B to select a sound and Up, Down, Left, or Right to play them.

Hold Down and power on the NES. Press Up on controller two after the screen turns white.

Press Select during game play to end the current game if you become stuck.

Enter FbgJ IYAX or GdBM IABg as a password to play additional levels.

Level 1 - HmnM LhBg
Level 2 - HPTZ hNDJ
Level 3 - JnCn hvcb
Level 4 - JQVP LrCH
Level 5 - KqGT hhCC
Level 6 - KRdv LNDV
Level 7 - LrFs LLCb
Level 8 - LSXq hfDG
Level 9 - Mtld hLCZ
Level 10 - NBqb nQCZ
Level 11 - NBqh hVCh
Level 12 - NVQK Lrcm
Level 13 - PChg nQCZ
Level 14 - PWMG LICH
Level 15 - QDgf nQCZ
Level 16 - QXJC LfCB
Level 17 - RZJH nnBg
Level 20 - NIEh VLBK
Level 25 - RXSh KKCB
Level 30 - TJBY EGCe

Hold A on controller two at title screen, until Kid Niki appears.

Hold Select and power on the NES. Press Up on controller two after the screen turns white.