NOTE: These codes may need tweaking, I will be remaking this video with more accurate descriptions.
30 Continues – At the title screen while holding down SELECT, press and hold the RUN button until the AREA – 1 text appears on the screen.
Don’t use any continue credits – At the GAME OVER screen Press SELECT 3 times, press and HOLD SELECT and press RUN.
Sound Test – Reset the game and when you see the 2 planets, HOLD SELECT and rock the D-PAD to the left and right as fast as you can until the sound test screen appears “SOUND 01”
Stage Select – Enter the sound test menu using the code above. Go to “SOUND 02” and press I, II, then keep tapping SELECT until a graphic / sprite shows up on the screen. The sound menu then turns into a stage select where you can choose stages or bosses.
Invicibility – Enter the sound test and stage select codes above, go to “SOUND 77” and press II, UP, DOWN. (This is under review, you may just have to press UP, DOWN, without any buttons.)
Lots of multi-bodies – Enter the sound test and stage select codes, go to SOUND 83 and press II, RUN (This is also under review until I make a new video)
Lots of Bombs and Lives – Enter the sound test and stage select codes above. While holding I, II and SELECT, select your stage and press RUN.
Select difficulty – Set button I and II auto fires all the way up, hold down I, II and SELECT and the MODE SELECT screen will appear. Use the select button to select the difficulty.