Alien Syndrome/Versions

Amstrad CPC
Developed by Softek and published on disk in Europe by ACE in 1988. Also published on cassette by Dro Soft.

Atari ST
Developed by Softek and published on disk in Europe by ACE in 1988. On par with the Commodore Amiga version described below.

Commodore 64/128
Ported by Ace. Supports 1 or 2 players, with a single player game started by pressing fire on Joystick Port 2.

Of note, the screen-scrolling is substandard, which is a low-speed scroll that allows pressing against the edge of the screen in normal play, which is dangerous due to approaching enemies.

There is 180 seconds on the clock, with a 60 second addition for reaching the boss. Unlike the arcade version, getting killed during the boss fight due to the timer doesn't require you to restart the full stage. However, you need to rescue all of the scattered comrades.

This port has significant changes on boss behavior:
 * 1) Asophy: The second phase of the boss is much more durable and faster.
 * 2) Hugger: Hugger only has four supporting blobs orbiting it, but they move quickly. Only two blobs get launched, but they're rather dangerous that you will need to alternate between them and the main target. If you can eliminate a few of the blobs and can get inside, you can quickly defeat hugger by rapidly firing.  Unlike the arcade version, the flamethrower is probably the best weapon as you can easily inflict damage on the orbs and keep the launched blobs at bay - or you can sacrifice a life and move behind Hugger and inflict damage without worry (although this tactic takes a full 100 seconds.)
 * 3) Tacapy: You only need to worry about hitting the body when the eyes are detached.
 * 4) Minnow: Minnow still launches a spread of shots, but no significant changes.
 * 5) Yocotie: While the attacks from the smaller holes have limited range, the main alien generally fires all the shots at you. Cover is one-way, your shots are blocked while Yocotie can return fire.
 * 6) Minenor: Only two things follow you, but they're slightly strong.
 * 7) Final boss: The suction attack is harder to dodge as the four clusters of air move more quickly. Instead of trying to dodge them, take cover in one of the corners, and move in and out of range of the attack.

Commodore Amiga
Ported by Ace. Supports 1 or 2 players, set by using the function keys. However, Rounds 4 and 5 from the arcade version are skipped. In Round 6, you're placed at the bottom-right corner of the map, requiring you to backtrack as you reach the bottom-left corner.

The time varies based on the round, but you normally receive 250 seconds on the clock. No bonus time is added when you reach the boss, and the time is reduced if you complete one of the loops. You also need to retrieve all comrades rather than just 10.

If possible, grab the laser weapon, as that does the most damage per second compared to the other weapons.

A quick boss guide based on the port:
 * 1) Asophy: The second phase of the boss is feeble. It is vulnerable when it slowly retrats to the upper-right corner, and is therefore minced in one cycle.
 * 2) Hugger: Hugger only has six supporting blobs orbiting it, and they're vulnerable to an early attack. Quickly move to the top of the boss arena, and destroy Hugger's blobs.  Once you eliminate the escort, you don't have to worry about the four tracking blobs it launches, as those leave the arena frequently.
 * 3) Tacapy: There are eight legs, but no obstacles. Destroy one side of legs on either the top or bottom, and try directing it to the same edge of the arena. Destroy the other legs, and you can hit the main body from the top or bottom.
 * 4) Minenor: With the laser, this boss is feeble as the attacks that follow you are easily destroyed.
 * 5) Final boss: The time limit of 100 seconds is more dangerous than the boss itself. The air suction is trivially dodged, but the vulnerable head on the top tends to be hard to hit.  Press against the boss and try to hit the weak point as it moves down.

Famicom / NES
Developed by Sanritsu and published in Japan by SunSoft on December 2, 1988. This was one of the Famicom games that Atari-owned company Tengen purchased the rights to distribute from SunSoft, and published for the NES in North America without license from Nintendo. Unlike other arcade to NES conversion which tended to alter the game mechanics, this conversion remains remarkably faithful to the original, and is far more accurate that Sega's own conversion of Alien Syndrome for the Sega Master System. This version even manages to include the two player simultaneous play. Changes from the arcade include:
 * Considerably slower speeds for the players and the enemies.
 * There are exactly 12 comrades in every station, and you must rescue all 12 before you can access the exit.
 * Limited to a smaller weapon selection: Fireballs, Lasers, and Flamethrowers. The S panel only returns the starting weapon.
 * No option robots. Bonus containers only ever provide 200 points.
 * Opening a W cabinet will instantly warp your player to another location on the station.
 * Bosses are simplified or entirely changed. All boss battles are presented against a black background.

MS-DOS
Developed by Softek and published in North America by Sega in 1989. On par with the Commodore Amiga version described above.

MSX
Developed by Xortrapa Soft and published by Dro Soft in 1988. Appears to have only been released in Spain. Not much is known about this conversion. For some unknown reason, its visuals appear to have been inspired by the weakest conversion of them all, the Sinclair ZX Spectrum version described below.

Sega Game Gear
Developed by Sims, and published by Sega around the world in 1992. Although the gameplay is extraordinarily similar to the arcade version, this conversion is more of a spiritual sequel. It reportedly takes place five years after the original Alien Syndrome.

Sega Master System
Developed by Sanritsu and published by Sega in Japan on October 18, 1987, and in North America in 1988. This conversion is the most altered of all home conversion. First and foremost, the overhead scrolling is completely removed, in favor of room-to-room exploration similar in style to the NES version of The Legend of Zelda. As a result, the stations are far more maze-like than their arcade counterparts. Animation is rough, and you have a smaller selection of weapons to choose from. Some bosses remain similar to the arcade while others are entirely new. For convenience, the maps for all six stations have been included below.

Sharp X68000
Developed by Dempa Shinbunsha, and published in Japan by Micomsoft in 1992. Like many other arcade conversions on the Sharp X68000, Alien Syndrome is considered a pixel-perfect accurate port of the original game.

Sinclare ZX Spectrum
Developed by Softek and published on disk in Europe by ACE in 1988. Also published on cassette by Dro Soft.