Observe the marked targets on the castle, adjust the shooting angle and press and hold the "shoot" button, release to shoot, and pass the level after breaking the castle
After breaking all the targets, he passes. In "Hard" mode, you will hit more targets, and the castle will also add a layer of shield. The shield can be eliminated by consuming 3 cannonballs or hit the center target on the shield. After completing the task, you can unlock some new cannons.