Alien Syndrome

Alien Syndrome
Arcade flyer
Developer(s)Sega
Sanritsu (NES, Master System)
Publisher(s)Sega
Composer(s)Tohru Nakabayashi (arcade)
David Whittaker (computers)
Noboru Machida (NES)
Platform(s)Arcade, Amiga, Atari ST, Commodore 64, Game Gear, MS-DOS, MSX, NES, Master System, ZX Spectrum, X68000
Release1987: Arcade, Master System
1988: Amiga, Atari ST, C64, Famicom, MSX, NES
1989: Spectrum, MS-DOS
1992: Game Gear, X68000
Genre(s)Run and gun, horror
Mode(s)Single-player, multiplayer
Arcade systemSega Pre System 16, Sega System 16B

Alien Syndrome (エイリアンシンドローム, Eirian Shindorōmu) is a run and gun video game developed by Sega and released in arcades in 1987, and later ported to the Master System the same year. The game utilizes a side-scrolling feature that allows the player to take control of either a male (Ricky) or female (Mary) soldier whilst hunting aliens and saving hostages before they run out of time.

Alien Syndrome released with a strong opening, becoming one of Sega's best-selling video games for the Master System. It received generally positive reviews, with praise towards the gameplay, character designs, sounds, and horror theme. It was included as a bonus game in the Genesis compilation game, Sonic's Ultimate Genesis Collection (2009). A sequel of the same name was released in 2007 to a strong negative response from critics.