Alexander Barnfield and Jakub Majewski
1
Freeware
Unknown Enemy is a fan made add-on for Wing Commander: Secret Ops.
Falco Software Company
8
Freeware
After working for decades in the special forces, I retired.
7
UFO:AI Team
370
Open source
UFO: Alien Invasion is a squad-based tactical strategy game.
2
OpenXcom Developers
151
Open source
It is an open-source clone of the original UFO: Enemy Unknown game.
4
Sean O'Connor's Windows Games
4
Shareware
In Windows Games UFOs you have to grab the crystals and dodge the enemies.
38
Splash Damage Ltd.
1,430
Commercial
Quake Wars is a Quake game that is played very much like Battlefield.
60
MyPlayCity.com
32
Ufo Killer game!
1
Returnil
40
Shareware
This program clones your operating system and creates a virtual environment.
Firaxis Games
432
Commercial
XCOM: Enemy Within is the expansion of the strategy game XCOM: Enemy Unknown.
1
Firaxis Games
772
Commercial
XCOM 2 is the sequel to XCOM: Enemy Unknown, strategy game.
Long War Studios
49
Freeware
Long War is a free mod for the 2012 game XCOM: Enemy Unknown.
1
xehonk
7
Freeware
It is an overhead view shooter in which you are caught in an unknown enemy base.
MyPlayCity, Inc.
40
Freeware
Set the town free from an unknown enemy in this first person shooter.
Falco Software Company
8
Freeware
Peaceful lands are invaded by an unknown enemy.
Falco Software Company
4
Freeware
The commander, our ships, met a new unknown enemy in the galaxy.
Falco Software Company
Freeware
An unknown enemy turned everyone who was on the space station into cyborg zombies.
