Viper Phase 1 is a 1995 scrolling shooter arcade game by Seibu Kaihatsu, and is a spin-off in the Raiden series. This game is often referred to as "Raiden in space".


The setting of this game is exclusively in outer space. Players pilot a space fighter through eight stages of enemy space fleets and tough bosses. Enemies include small space fighters, space cruisers, space frigates, and entire space installations. Gameplay is similar to the Raiden series.

Scoring is straightforward. 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.

The end game bonus is tallied in this way:

  • 1,000,000 points for completing the game
  • 100 points for each enemy killed throughout
  • 1,000 points for each medal collected throughout
  • 500,000 points for no bombs used
  • 500,000 points for not dying, 100,000 points lost per death to a minimum of 300,000

Differences in the New VersionEdit

A newer 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:

  • Secondary Weapons Systems: The old version of Viper Phase 1 has an exhaustible secondary weapon system. The amount of ammunition remaining in a secondary weapon is indicated by a meter on the screen. All secondary weapons in the original version are fully powered up, and are more devastating than in the new version, which gives the secondary weapons levels of power in lieu of unlimited ammunition and reduced firepower.
  • Bomb Deploy Times: The new version speeds up the deploy time of the Bomb, of which becomes the standard for when the ship appears in the Raiden Fighters series.
  • Medals: In the New Version, medals stop shimmering for a brief moment, during which their point values are higher than usual. This feature was also present in Raiden DX. Additionally, the egg-shaped medal carrier pods appear much more frequently in the New Version.

Types of PowerupsEdit

There are 6 types of powerups in Viper Phase 1. They are released by destroying certain enemies. Players start with a primary vulcan cannon on each new life. P (Power Up) - Old version: Powers up the main vulcan gun only. New version: Powers up the vulcan (if the player is without secondary weapons) and the active secondary weapons (up to four levels).

  • B (Bomb) - Adds one extra bomb. Players can carry up to seven bombs in stock. Extraneous pickups of the Bomb icon awards the player with 1,000 bonus points.
  • L (Laser) - This weapon is similar to the blue laser weapon in the original Raiden series. The weapon has no defensive spread. However, the Laser is the most damaging secondary weapon available. It can make short work of large enemies and bosses. Ship's weapon module flashes blue.
  • M (Burst Missile) - Cruise missiles that are fired in a burst pattern. When the missiles hit their mark, the resulting explosion deals overlapping secondary damage. Ship's weapon module flashes yellow.
  • N (Napalm Missile) - Upon impact with an enemy target, this secondary weapon releases green napalm explosions in various directions. These explosions deal overlapping secondary damage. When fully powered-up, the cluster of explosions cover a substantial part of the screen, and may obscure enemy firepower. This weapon became famous when it was included in the Raiden Fighters series as a cameo along with the ship (later named Judge Spear). Ship's module flashes green.
  • W (Wide Vulcan) - Grants the player with a secondary wide-spread vulcan cannon. The spread of this weapon is useful in destroying enemies in many locations at once. The firepower, however, is the weakest of the four secondary weapons. Using this weapon at point-blank range on one enemy can deal moderate damage. Ship's module flashes red.


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 duaghterboards and Seibu SPI main boards are region-specific. For example, the Japanese daughterboards are not compatible with the European motherboard and vice versa.


1 Spaceport Go Straight Ahead!!
2 Space Fleet 1 Outer Space
3 Refueling Base Mission Striker
4 Storage Facility Forcing Breakthrough
5 Asteroid Belt Invisible Enemy
6 Space Fleet 2 Counteroffensive
7 Space Colony Unknown Threat
8 Missile Silo Destiny


The soundtrack of Viper Phase 1 is composed by Go Satoh. 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 soundtrack is available as an unlockable in the Japanese-only release of Raiden DX for the Sony PlayStation. When unlocked, players have the option of changing the default Raiden DX soundtrack to implement music from Viper Phase 1.

External LinksEdit

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Raiden series
Main Series Raiden - Raiden II (DX) - Raiden III - Raiden IV (Overkill) - Raiden V
Raiden Fighters Series Raiden Fighters - Raiden Fighters 2: Operation Hell Dive - Raiden Fighters Jet
Conversions The Raiden Project - Raiden Fighters Aces - Raiden Legacy
Other Seibu/MOSS shmups Stinger - Scion - Air Raid - Viper Phase 1 - Caladrius (Blaze)