Time attack boss mode:
After defeating the final Boss he will hang from the tower. Shoot the chain and complete the game that way.

Survival boss mode:
After defeating the final Boss he will hang from the tower. Shoot him or the girl and they will fall both.

3 credits:
Continue the game more than 15 times.

4 credits:
Continue the game more than 30 times.

Endless credits:
Continue the game more than 100 times.

Extra lives:
First lose all lives and then the game itself. You will increase the lives to 4 or 6 when you continue to do this.

Extra time:
Lose the game with the timer nearly 0. You will increase the time to 70 or 80 when you continue to do this.

Exchange half of your lifes for 5 seconds:
Pause the game, then press Up(2x), Down(2x), Left, Right, Left, Right, X, Circle.

Exchange 5 seconds for half of your lifes:
Pause the game, then press Circle, X, Right, Left, Right, Left, Down(2x), Up(2x).