This is a sort of action defense game. You are a knight and you need to protect the king's castle at any cost. The enemies will appear in waves at the other side of the bridge. You can move your knight with the arrow keys and hit the enemies with your sword pressing space. You need to kill them all before they reach the castle and get a chance to harm it. You can open skills dialog pressing S and spend the experience points you have earned to learn new spells and improve the old ones.