Out Zone[a] is a run and gun arcade video game developed by Toaplan and published in Japan by Tecmo, North America by Romstar and Europe in August 1990.

Set in a future where an alien race from the fictional planet Owagira are threatening to wipe out humanity after multiple failed attempts to defend Earth against their attacks, players assume the role of cyborg mercenaries recruited by the United Nations in a last-ditch effort to overthrow the invaders.

Out Zone is a science fiction-themed vertically scrolling run and gun game reminiscent of Commando and Ikari Warriors, where players assume the role of two cyborg mercenaries hired by the United Nations through seven increasingly difficult levels, each with a boss at the end that must be fought before progressing any further, in a last-ditch effort to overthrow an alien race from the planet Owagira from invading Earth as the main objective.

Other weapons appear on certain occasions as different colored "SP" icons to acquire, like a flamethrower and a rotating energy ball capable of piercing walls.

Under desperation and as a last-ditch effort to counterattack Owagira's military force, the UN requests Out Zone's service, guaranteeing the UN member nations' entire annual budget as payment.

[7][8][9][10] Uemura recounted its development process and history in interviews, stating that it was difficult for him as he could not apply his experience from vertical-scrolling shooters with flying ships, as players controlled the game on-foot and could not design its progress.

[10] The project was fundamentally different due to the lack of forced scrolling, which did not require skills from vertical shoot 'em ups and players could move or stop freely.

[8] The team integrated puzzle elements not found in ship-based shooters, which took time to plan out and Uemura said that the schedule for sound production was constantly being reduced, barely implementing the music during development.

[10] For the first stage's music, Uemura revealed in response to a user on Twitter that the main melody was originally composed based on Taiyō ni Hoero!.

[12][13][14][15] On October 21 of the same year, an album containing music from the title and Snow Bros. was co-published exclusively in Japan by Scitron and Pony Canyon, featuring an arranged song composed by Uemura.

[35] Sinclair User praised the fast-paced gameplay and frenetic action, stating that "Outzone is one hell of a challenge, particularly past the initial stages, but is sure to set the pulse racing if you've got the reactions to match it!".