From Wikipedia
Phoenix is a popular shoot 'em up arcade game created and manufactured by Amstar Electronics (which was located in Phoenix, Arizona) in 1980, and licensed to Centuri for US distribution, and to Taito for Japanese distribution.
Like many arcade games of that era, Phoenix is a top-down outer space-themed fixed shooter. The player controls a spaceship that moves horizontally at the bottom of the screen, firing upward. Enemies, typically one of two types of birds, appear on the screen above the player's ship, shooting at it and periodically diving towards it in an attempt to crash into it. In addition to the missiles, the ship is equipped with a shield that can be used to zap any of the alien creatures that attempt to crash into the spaceship. However, the player cannot move while the shield is active, and must wait for a short period (approximately five seconds) before using it again.
Phoenix was one of the first full color arcade games, along with Galaxian, so at the time it stood out. Also, it has distinctive shooting sounds that have become very familiar to fans of the genre. Most importantly, the Phoenix mothership was the first video arcade game boss where the boss was presented as a separate challenge.