After the games has been loaded, click "New Game". The king tells what you must do for protecting the castle from the aliens. Go to the place that buying weapon and ammunation by pressing "Next". Buy the weapon from top line, buy ammunation of the the selected weapon from middle line and you can buy castle repairing, shield or bombs from the bottom line. You can see your total money at the top left. You must earn more monay to buy expensive things by passing the levels. After selecting weapon and ammunition click "Next" to start war. Use your keyboard and mouse. Fire with mouse, arrow keys to change weapon, space button to send bomb. Protect your castle from the aliens now!