Metal Slug 2

Hint: Level 1: Assistant:
On the first level is a slave about mid-way through. Free him by shooting him and he will follow you through the rest of the level, shooting what seems to be kamehameha waves at the enemies.
Information in this section was contributed by JGothman326.

Hint: Level 1: Hidden prisoners:
At the beginning of the level when you face the person on the camel, do not go any further after you kill him. The middle tree in that screen will drop a lot of bananas and two prisoners when shot at.

Hint: Level 2: Easy points:
In the second mission, shoot any eye in the level that you see on the walls and you will get rubies. You can also shoot where the mine workers have been digging. Jump up and shoot down while you are in the air.
Information in this section was contributed by Alan A.