Code

Here are some codes I found on the net.

Descriotion Code Pic

Start with Lamp
(continue) At the title screen press and hold Up+Select+I, then press run. When the game starts, you will have the lamp.

Start with Hyotan / bottle
(recover some HP) At the title screen, press and hold Up+Select+II, then press Run

Funny Sprites At the title screen, press Up, Down, left, right, I, II, run and most of enemies will be you.

Black and White Mode (does not work on emulator) At the title screen, press and hold Up + I + II, then press Run. N/A

Strange Demo Mode During the Demo, press and hold I to prevent the computer from being able to Jump; pressing and holding II will prevent the computer from being able to Attack. N/A

Descriotion	Code	Pic
Start with Lamp (continue)	At the title screen press and hold Up+Select+I, then press run. When the game starts, you will have the lamp.
Start with Hyotan / bottle (recover some HP)	At the title screen, press and hold Up+Select+II, then press Run
Funny Sprites	At the title screen, press Up, Down, left, right, I, II, run and most of enemies will be you.
Black and White Mode (does not work on emulator)	At the title screen, press and hold Up + I + II, then press Run.	N/A
Strange Demo Mode	During the Demo, press and hold I to prevent the computer from being able to Jump; pressing and holding II will prevent the computer from being able to Attack.	N/A