Ride your castle and fight against the alien invasion to the end. Rescue the falling princesses and fight the big boss to release any of the captured ones. The waves of enemy spaceships and tanks will keep storming your city with deadly weapons and lasers. Use the arrow keys to move your castle and the mouse to aim and shoot towards the incoming enemy. Upgrade your castle, bastion, drum tower, barbican and several other items to fight the furious enemy with more power. It is your responsibility as the king to save your city. There are several levels with different backgrounds which makes the gameplay a lot more interesting.