As soon as Sand Castle 2 starts you will have to buy a few projectiles which will help you sink the incoming enemy ships. After you purchase what you need, the attack will begin. You can switch between projectiles anytime you want, but each change will cost you a few seconds. Enemy vessels will stop near your castle and start firing. You have to use your mouse for aiming and shooting. After you figure out the perfect angle, you just have to click and hold the left mouse button and the power bar will appear. When you release the button, your projectile will be fired. In Sand Castle 2 you will have to keep an eye on the life bar of each battleship and make sure that you terminate each and every one of them. In some cases a projectile can turn a ship upside down. If this happens, it won't be able to attack you anymore, but you still have to hit it a few more times until its life bar is completely drained. If you are fast enough, you will receive gold which can be used for buying bigger and better projectiles.
Sand Castle 2 is a fun game to play, especially once you get used to the controls. You need to aim perfectly if you want to have a high score, but most of your targets won't be stationary and this is why you need to act fast.