Super weapon:
Collect the following power ups in order, then intentionally lose all shields: Red, Blue, Green, Green, Yellow, Red. REMEMBER: Collecting Shield or Invincibility power-ups will not spoil activation of the code.

Unlimited continues:
Hold I + II + Select and press Run at the title screen or at the "Game Over" screen.

Resume reset game:
Reset the game, then hold I + II + Select and press Run at the title screen to resume game play at the last level played.