Enable Sound Test cheat. Press I, II, than keep pressing Select until the debug screen appears. You can now do the following:
---1. Code: Use level select to go onto which level you want, then hold I and II and press Start to begin gampleay with 10 lives and 10 bomb
Result: Extra Lives, Bombs, Power
--- 2. Code: Enter 83
Result: Half Game with lots of Satellites
--- 3. Code: Enter 77. Press Up, Down before leaving debug screen.
--- 4. Code: Enter 00 (level 0) - 09 (level 9)
Result: Level Select
''Normal Dog'' or ''Hard Human'' difficulty
Place I and II on top turbo speed and hold down I, II and Select simultaneously
Hold Select and alternately press Left and Right repeatedly until 'Sound 01' appears.
--- 1 Code: At the title screen, hold Select and press Run until the phrase 'Area 1' appears.
Result: 30 Continues
--- 2 Code: Enable the Sound Test cheat. Press I, II, Select 22 times. Then hold Select and Run until the game starts.
Result: Area 0, 30 continues
--- 3 Code: Hold Select and alternately press Left and Right repeatedly until 'Sound 01' appears.
Result: Sound Test
--- 4 Code: Hold Right, and keep pressing Run quickly at the title screen.
Result: View Ending
''Super Mania'' or ''God of the Game'' difficulty
Place I and II on low turbo speed and hold down I, II and Select simultaneously