Defend your catapults against the invading ships! Use WSAD or the arrow keys to move around the map, and hit Space or Enter to place your defenses. Pressing Tab will swap between building Castle Walls and Catapults. You get points for destroying enemy ships, the enemy gets points for destroying your catapults

Walls cost 10 Stone to build and 5 Stone to repair
Catapults cost 10 Wood to build and 5 Wood to repair
Shooting mountains gives you stone
Destroying ships gives you wood