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.
4
Sean O'Connor's Windows Games
4
Shareware
In Windows Games UFOs you have to grab the crystals and dodge the enemies.
7
UFO:AI Team
370
Open source
UFO: Alien Invasion is a squad-based tactical strategy game.
79
Novel Games Limited
3
Freeware
Five UFOs is a nice memory game in which you must click the flying saucers.
2
OpenXcom Developers
151
Open source
It is an open-source clone of the original UFO: Enemy Unknown game.
1
ALTAR Interactive
224
Shareware
UFO Aftermath is a tactical game where you must repel an alien invasion.
Firaxis Games
432
Commercial
XCOM: Enemy Within is the expansion of the strategy game XCOM: Enemy Unknown.
1
Firaxis Games
770
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.
Oberon Media
3
Shareware
Explore distant and unknown lands with three games in one.
