Alien Syndrome

 is a run and gun game developed by Sega and released in arcades in 1987.
Gameplay.
Two players control two soldiers, named Ricky and Mary, who fight their way through large eight-way scrolling levels while rescuing their comrades who are being held by aliens. After they have rescued a certain number of hostages, the exit opens and they can pass through it in order to fight the end-of-level guardian. If this monstrosity is defeated, they are then able to move onto the next stage.
"Alien Syndrome" features two player simultaneous gameplay and pickups which assist the player, including better weapons and maps of the current level.
Ports.
In 1988, the game was ported to the Master System, MSX, Amiga, Atari ST, Amstrad CPC, Commodore 64, and Famicom/Nintendo Entertainment System (published by Tengen without a Nintendo license). Later, the game was ported to the ZX Spectrum (1989) Game Gear (1992) and Sharp X68000 (1992), the latter being the only arcade perfect port.
Reception.
In Japan, "Game Machine" listed "Alien Syndrome" on their May 15, 1987 issue as being the third most-successful table arcade unit of the year. The original arcade version of the game was reviewed in the July 1987 issue of "Computer and Video Games", where Clare Edgeley described it as "one of the most gripping games" she "played in months", praising the "Aliens"-like horror atmosphere, chilling sounds, special effects, graphics and gameplay. She stated it was "the first time the atmosphere and sheer addictiveness of a shoot 'em up has transported me to another planet" and concluded that it "is fantastic".
The Master System version of the game was reviewed in 1989 in "Dragon", getting two out of five stars.
Legacy.
The game was also converted to polygonal graphics for the PS2 as part of the Sega Ages re-release program and included in the US version of the "Sega Classics Collection" (it was removed from the European version to receive a lower age certificate). This version has updated controls, adding the use of both analog sticks, similar to that seen in "Sheriff", "" and "Smash TV". The original arcade game was also included as an unlockable in "Sonic's Ultimate Genesis Collection".
A sequel of the same name, "Alien Syndrome", was released for Wii and PSP on July 24, 2007.