The game was ported to the Famicom (by [[Sunsoft]] and [[Sanritsu]]), [[Sega Game Gear]] (published by [[Sims]]) and [[Sega Master System]]. In 1988, [[Tengen]] brought Sunsoft's port over to the United States with an unlicensed release, removing both Sunsoft's and Sanritsu's names. Due to technical restrictions, some versions are single-player only. It was also re-released as part of the [[Sega Ages 2500]] series and as part of ''[[Sega Classics Collection]]'' (however it was removed from the European release to keep the [[PEGI]] rating down). The ''Sega Classics Collection'' port is notable for its two joysticks control scheme, similar to ''Robotron 2084'' and ''Smash TV''.
The game was ported to the Famicom (by [[Sunsoft]] and [[Sanritsu]]), [[Sega Game Gear]] (published by [[Sims]]) and [[Sega Master System]]. In 1988, [[Tengen]] brought Sunsoft's port over to the United States with an unlicensed release, removing both Sunsoft's and Sanritsu's names. Due to technical restrictions, some versions are single-player only. It was also re-released as part of the [[Sega Ages 2500]] series and as part of ''[[Sega Classics Collection]]'' (however it was removed from the European release to keep the [[PEGI]] rating down). The ''Sega Classics Collection'' port is notable for its two joysticks control scheme, similar to ''Robotron 2084'' and ''Smash TV''.
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A [[Alien Syndrome (2007)|sequel with the same name]] was released for the [[Wii]] and [[PSP]] in 2007.
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A scrapped sequel was planned for the [[Sega System 24]] by the first game's designer [[Hiroshi Aso]], set to include more strategic elements and branching stages{{fileref|SegaAges2500_V14_PS2_JP_Leaflet.pdf|page=2}}. Instead, a [[Alien Syndrome (2007)|sequel with the same name]] was released for the [[Wii]] and [[PSP]] in 2007.
Alien Syndrome (エイリアンシンドローム) is a 1987 arcade game released by Sega. It runs on Sega System 16 hardware. The user plays as either Ricky and Mary rescuing hostages within a set time limit while blasting aliens. There are numerous weapons and two players can play simultaneously.
Compared to other Arcade ports to the Master System, Alien Syndrome shows some very poor production values. It's incompatible with the Mega Drive controller (since the Master System D-pad is terrible for the diagonals), lacks a cooperative 2P mode (it only have the competitive one) and lacks a scrolling camera.
The game was ported to the Famicom (by Sunsoft and Sanritsu), Sega Game Gear (published by Sims) and Sega Master System. In 1988, Tengen brought Sunsoft's port over to the United States with an unlicensed release, removing both Sunsoft's and Sanritsu's names. Due to technical restrictions, some versions are single-player only. It was also re-released as part of the Sega Ages 2500 series and as part of Sega Classics Collection (however it was removed from the European release to keep the PEGI rating down). The Sega Classics Collection port is notable for its two joysticks control scheme, similar to Robotron 2084 and Smash TV.