Pleiads (プレアデス) is an arcade game produced by Tehkan (now Tecmo) and Centuri, loosely based on an earlier game called Phoenix which was produced by Amstar in 1980.
Pleiads is a multi-stage space shoot 'em up in which enemy ships fly at you in waves in a similar fashion to games like Galaxian and Phoenix. Ships emerge from a mothership at the top of the screen and swoop downwards in a series of patterns which players must anticipate as they shoot the ships and avoid being obliterated by the Martian onslaught. There are four stages in the game. In the first stage the Earth space ship must defend the space station from Martian invaders who have the ability to transform from flying invaders, to walking invaders who build walls across the Earth city; these barriers must be destroyed. At the end of stage one the Earth space ship flies to the top of the screen to prepare to meet stage two. In the second stage the player encounters eight space monsters who must be hit directly on center to be destroyed before moving onto stage three. In this stage invaders emerge form a space ship at the top of the screen and swoop down on the player in sweeping attacks. In the final wave the player has to negotiate parked spaceships to dock on a landing pad as the screen scrolls downwards. Extra points can be gained in this stage by collecting flags as you negotiate the landing corridor.
Trivia! Pleiads was featured in the 1983 horror film, "Nightmares" in the vignette "Bishop of Battle." Pleiads also made a cameo appearance in the 1984 Coen Brothers directorial debut and neo-noir motion picture Blood Simple.
Source: Wikipedia, "Pleiads", available under the CC-BY-SA License.