Aliens in their flying saucers have invaded Earth and have set their sights on destroying the capital of the USA, Washington D.C and all it's landmarks. You have been given the task of destroying the invaders by blasting them with your Energy gun in a bunker outside the city. The game is viewed from a 1st person perspective with the game shown on one screen and you control a gun sight to blast the saucers before facing the Mothership in space. To face and destroy the Mothership you must get 150 points before the aliens get 50 points. Blasting the saucers get you various points while for every three seconds on screen and destroying a landmark, an alien gets points. If the aliens get 50 points or manage to land then it is game over. You start the game in the daytime and the game moves into the evening and then night time for every 50 points. Once you have got 150 points then you can face the Mothership in space and this entails trying to shoot it's Command Module on the top but you can decrease it's shield hitting elsewhere on the ship. The joystick is used to control your gun sight.