By throwing spiked cannonballs, you must knock the maximum number of blocks off the platform in Block Destroyer. In the upper left corner you will see the task. It means the minimum number of blocks you need to knock off the platform. If it is not enough, you will have to go through the level again. You have three hits to knock down. In the lower right corner there is a number of attempts. Try to make the most of every hit. It is important to find a weak point in the building that will provoke global destruction and you will quickly complete the task in Block Destroyer.