Cybernator

Six continues:
Hold Up + L + R, and press Start at the Konami screen.

Nine continues:
Hold L + R and press Start(5) at the title screen.

Napalm gun:
Walk through the first mission without shooting or hitting any targets. Your score should be 0 points. Defeat the Boss without shooting its side gun turrets. Your score should be 2,800 points. When the asteroid level begins, press X to change weapons until the unlimited napalm gun is selected. Complete this mission without dying to keep the unlimited napalm for the remainder of the game. Note: It cannot be powered up.

Upraded Napalm gun:
Complete the second mission without hitting or shooting anything execpt for the Boss. You can now upgrade the Napalm Gun. When upgraded to level 3 its fireballs will bounce off walls.

Hint: Failed ending:
Go through the first level, and do not destroy the Boss. Finish the rest of the game to see the failed ending in which everyone dies.
Information in this section was contributed by thomas kwan.