Hold Select, press Run at the title screen, and wait until the phrase "Area 1" appears.
Enable the "30 continues" code. When the current game ends with 30 continues remaining, press Select, Select, then hold Select + Run until the game restarts.
Hold Select while tapping I, II repeatedly at the title screen. Press Select to choose between four difficulty levels. Begin game play by holding Run and press Select. Alternatively, enable the Turbo switches and press I + II to start the first part of the code.
Area 0, 30 continues
Enable the "Sound test" code. Press I, II, Select twenty two times. Then, hold Select + Run until gameplay begins.
Enter 00 - 09 as a debug number.
Enter 77 as a debug number, then press Up, Down before exiting the debug screen.
Half game with many satellites
Enter 83 as a debug number.
Hold Select and alternately tap Left, Right repeatedly until "Sound 01" appears.
Enable the "Sound test" code. Press I, II then tap Select repeatedly until the debug screen appears. The following debug functions may now be enabled.
16 lives, 36 bombs
Avoid and do not shoot the Boss at the end of any odd numbered level. After the Boss leaves, 16 lives, 36 bombs, and a double score will be awarded.
View ending sequence
Hold Right and quickly tap Run at the title screen.