Gunblade NY

Both guns for two coins:
When instructed to put in your tokens or coins, use two coins. When the buttons start to flash, press both simultaneously.
Information in this section was contributed by Z.C.

Alternate ending sequences:
Finish the game without using any continues under easy or difficult mode. Butterflies will appear. Do not destroy the missile carrier truck at the end of the second stage under the difficult mode. Your superior officer will hit you. Pull the machine gun triggers during the ending sequence under easy mode. A giant dragonfly will pass by. Pull the machine gun triggers during the ending sequence under difficult mode. A submarine or shark will follow the ship.

Hint: Shootable rockets and bullets:
If an enemy shoots a weapon, shoot the bullet or rocket. If you do not, a life is lost. If all lives are lost, insert another coin, or if you have any credits, press P1 or P2. Do not pull the trigger on the gun. If you do, when you have still got enough credits, it is a game over.
Information in this section was contributed by johnlmth.