From Wiki: "Saucer Attack is a computer game for the Commodore 64, created by James D. Sachs.
The game is a shoot 'em up where the player's job is to protect Washington, D.C. from invading flying saucers. The game screen presents a beautifully drawn backdrop of Washington, with various landmarks such as the Washington Monument visible. After a while, flying saucers start to descend from the top of the screen. The player has to move a crosshair at the saucers and fire bullets to destroy them. If allowed to proceed unharmed, saucers will hover near a famous landmark and shoot a beam of electricity at it, eventually destroying it. If all landmarks are destroyed, the game is lost."(1)
Saucer Attack for the Commodore 64 was the first game James D. Sachs wrote. He marketed it by mail-order, and had fairly good success with it. It got some great reviews in the C-64 magazines.(2)
(1) Source: Wikipedia, "Saucer Attack", available under the CC-BY-SA License.
(2) Source: The Developer Website.