Ugh!

Inspired game: CaveExpress

Ultima III: Exodus

Inspired games: Anteform, Minima

Ultima IV: Quest of the Avatar

Inspired game: xu4

Ultima Online

Inspired games: ClassicUO, CrossUO, Iris2

Ultima series

Inspired game: Haxima

Ultima Underworld 1

Inspired games: Underworld Adventures, UnderworldExporter

Ultima Underworld II: Labyrinth of Worlds

Inspired games: Labyrinth of Worlds, UnderworldExporter

Ultima V: Warriors of Destiny

Inspired game: Ultima 5 Redux

Ultima VI: The False Prophet

Inspired game: Nuvie

Ultima VII: The Black Gate

Inspired game: Exult

Ultima VIII: Pagan

Inspired game: Pentagram

Ultima: Worlds of Adventure 2: Martian Dreams

Inspired game: Nuvie

UltraStar Deluxe

Inspired game: Vocaluxe

Undertale

Inspired game: UndertaleModTool

Uninvited

Inspired game: uninvited

Uniwar

Inspired game: Hexwar

Unreal Tournament

Inspired games: SurrealEngine, UTEngine

Urban Assault

Inspired game: UA_source

Urho3D

Inspired game: Alimer