X-COM: Apocalypse

Inspired games: Open Apocalypse, OpenXcom, UFO2000, UFO: Alien Invasion, X-Force: Fight For Destiny, Xenowar

Media: X-COM: Apocalypse

X-COM: Enemy Unknown

Inspired game: Project Helena

Media: X-COM: Enemy Unknown

X-COM: Terror from the Deep

Inspired games: Open Apocalypse, OpenXcom, SR, UFO2000, UFO: Alien Invasion, X-Force: Fight For Destiny, Xenowar

Media: X-COM: Terror from the Deep

X-COM: UFO Defense

Inspired games: Open Apocalypse, OpenXcom, SR, UFO2000, UFO: Alien Invasion, X-Force: Fight For Destiny, Xenowar

Media: X-COM: UFO Defense

X-Moto

Inspired game: Bloboats

Xargon

Inspired game: Xargon

Media: Xargon

xBaK

Inspired game: BaKGL

XKobo

Inspired game: Kobo Deluxe

Xonotic

Inspired game: Chaos Esque Anthology

XOR

Inspired game: XorCurses

Media: XOR

XPilot

Inspired game: XPilot NG

XRay engine

Inspired game: Oxygen Engine

Xtank

Inspired game: nXtank