Based on the Charlie the Chimp games. It contains 50 levels. In two player mode the second player is Penguin Pete.
Start the game and when it says [LEVEL 01] in the middle of the screen type "JESSICA". This will give you ten extra guys. You can type this in twice or maybe three times and you will get ten extra guys added to your current stock each time. This can also be done at the start of any level.