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 | 
| Release | 1987: 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 system | Sega 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.