This game uses an original concept, it doesn't use crystals to show where your character is, but the characters are painted on the background in color and the crystals block out the parts of the screen that aren't meant to be seen at that moment. Only a few games use this concept, probably because it doesn't really work that well, the sprites that are supposed to be blocked can always be partially seen underneath, especially at the edges of a crystal, making it sometimes unclear at which position your character really is.
You play a prisoner who ,of course, wants to escape. In the middle of the night you leave your bed at the top right of the screen and work your way to the wall to the upper left, once there 'left' has to pushed a few times to slowly break down the wall. Along the way you have to watch out for the searchlight which moves back and forth, when you get caught in it a miss will be registered. There are two places where you can hide from the light, behind the barrel and in the bushes. You also have to make sure the guard and his dog don't catch you while you are picking the wall. If you take too long in one escape another guard will appear to the right and walk up to your prison cell and he'll notice someone missing, you can prevent this by quickly running back and jump back into your prison bed until he leaves again.
Although the 'blacking out' system doesn't work that well it's still a beautifully designed game and fun game to play for a while.