The Peace Keepers Cheats

If you play as Prokop up to the Ozymandias stage, then play as any other character on that stage, Prokop will be killed when you go down the flight of stairs.

If you go up to the door at the end of the Roy D Tutto Hospital stage without going in, then return to the manhole you passed in the street, you will find it is open. It is a shorcut to the Stalag 17 stage

If you go up to the door at the end of the first stage without going in, then return to the beginning, you will find a secret character