Convert Health to Time:
Press Start to pause game play in arcade mode, then press Up, Up, Down, Down, Left, Right, Left, Right, , . The sound of a gun will confirm correct code entry. One half of a life will be converted into five extra seconds. This code can be repeated.

Convert Ttime to Health:
Press Start to pause game play in arcade mode, then press , , Right, Left, Right, Left, Down, Down, Up, Up. The sound of a gun will confirm correct code entry. Five seconds from the timer will be converted to one half of a life. This code can be repeated.

Three Credits:
After continuing the game 16 times, you will be able to increase the credits to three on the options screen.

Four Credits:
After continuing the game 31 times, you will be able to increase the credits to four on the options screen.

Unlimited Credits:
After continuing the game 101 times, you will be able to increase the credits to infinite on the options screen.

Additional Lives:
Intentionally lose the game by dying repeatedly to increase the number of lives per credit between four to six.

Additional Time:
Intentionally lose the game by allowing the timer to run out repeatedly to increase the time limit between seventy and eighty.

Time Attack Boss Mode:
After you defeat the big Boss by shooting him three times, he will hang from the tower. Shoot the chain and complete the game that way to unlock time attack boss mode.

Survival Boss Mode:
After you defeat the big Boss by shooting him three times, he will hang from the tower. If you shoot him or the girl, they will both fall. You will complete the game and unlock survival boss mode.

GameShark Codes

(M) Must Be On  
EC8816A014465F34  

Inf Credits  
4CB1A99C1456E7A7  

Inf Health P1  
4CB48B741456E6A5  

Inf Time  
4CB48BA61456E70C  

No Reload  
4CB48B9A1456E7A3  

Thanks to Revolution reader pooty!