Your mission is to make sure the balls go down the barrel. As the name suggests, you have to pull the pins one after the other. However, the challenge is that you have to pull them in the correct order. There is also a trick to the game, which is that you have to make sure that the colored balls hit the colorless ones, so that the colorless ones change color. Only painted balls are allowed to fall into the tank. The game becomes more challenging with each level, mainly because more pins have to be moved. The technique in all levels is to remember that you have to make sure that the gray balls touch the colored balls first before they all reach the tank. If not, the gray balls will turn to dust and you will have to repeat the level.
If you think you will only be dealing with colored balls and colorless balls and pins, you are wrong. pull the pin also has bombs. If you pull the first pin where the bomb is, it will fall down the balls and eventually explode. The explosion will cause some orbs to fly off the screen, meaning you need to replay the level.