Alpha Mission is a vertical shooter arcade game which was created by SNK in 1985, and ported to the NES in 1986. It was originally named "ASO: Armored Scrum Object" in Japan.
Alpha Mission is a one-player scrolling shooter game, similar to Xevious in its obvious segregation of air-to-air and air-to-ground weapons. Laser-like weapons are used for aerial opponents, while missiles are used to destroy ground enemies. Throughout each of the levels, the player must fight off waves of enemies while defending several space stations. A boss must also be defeated at the end of each level.
Like most early games in this genre, when the player dies, all weapons are lost and the player is moved to a point slightly before the point of death. Also, the player's aircraft can be upgraded to with more powerful weapons by picking up various power-ups throughout the level.
Alpha Mission is followed up by Alpha Mission 2 which was only released in arcades and for the Neo Geo.