Viper Phase 1
Gameplay. The game is set in outer space. Players pilot their space fighter through eight stages of enemy space fleets and bosses. Enemies include small space fighters, space cruisers, space frigates, and entire space installations. A bonus is assessed at the end of each stage taking into account the number of medals collected, the number of enemies destroyed, the number of bombs in stock, and the total kill percentage. At the end of the game, a grand tally is assessed. Factors taken into account are the number of continues used and the number of lives lost. Plot . By the year 2050, mankind begins the colonization of multiple planetary systems in the search for habitable planets. While the colonists establish original cultures and scientific studies, many of them begin feuding with each other. Armed conflict breaks out among them and the Earth. One rebel faction rises to great power and makes Earth their primary target. Earth's response is Operation Viper Phase 1: to combat the rebels using advanced space fighters built from downed enemy ships. Differences in the new version. A new version of "Viper Phase 1" was released with gameplay changes. The new version is known  as Viper Phase 1: USA in the United States. The known differences between the versions: Powerups. There are six types of powerups in "Viper Phase 1". Players start with a primary vulcan cannon on each new life. Music. The soundtrack of "Viper Phase 1" was composed by Go Sato. Its style is vastly different from the original Raiden series, incorporating many synthesized instruments. The soundtrack was released in 2005 as part of a superplay DVD set showing expert players playing through the game. The official track listing: The soundtrack is available as an unlockable in the Japanese-only release of  Raiden DX for the PlayStation. When unlocked, players have the option of changing the default Raiden DX soundtrack to implement music from "Viper Phase 1". Hardware. "Viper Phase 1" runs on the Seibu SPI System hardware. The game software is stored on ROM daughterboards that are interchangeable on one SPI board. ROM daughterboards and Seibu SPI main boards are region-specific. For example, the Japanese daughterboards are not compatible with the European motherboard and vice versa. Reception. In Japan, "Game Machine" listed "Viper Phase 1" on their July 1, 1995 issue as being the ninth most-successful arcade game of  the month. In North America, "RePlay" reported "Viper Phase 1" was the sixth most-popular arcade game at the time. A critic for "Next Generation" praised the game's beautiful visuals and increasing level of difficulty, but added that "like all shooters, unless your hand-eye coordination is really solid, the fun will pass you right by". He gave it three out of five stars.