Licensed by Phoenix, Arizona-based Amstar to manufacturer Centuri, Phoenix expanded upon the highly popular "invading aliens" format with a wider and more varied range of challenges. Players first fight invading waves of bird-like creatures, which start in formations and dive in patterns, before moving on to larger and more dangerous birds and finally fighting a boss-like alien spaceship that players must shoot through in stages to defeat. Though it lacks the fluid grace of contemporaries like Galaga, the game makes up for it with a degree of complexity and variety not found in most similar games.