Pterodactyl Software Ltd      2000

Unreal PSX was a cancelled port of Epic MegaGames' Unreal for the PlayStation console, featuring an entirely new single player campaign. The PlayStation Unreal port was a sequel to the events from Unreal and Return to Na Pali, developed by Pterodactyl Software Ltd in 1998-2000. Cancelled by the will of Infogrames, the game was almost completely forgotten. However, in 2009, an Unreal community member Leo(T.C.K.) has made numerous attempts to acquire the content that was already made and finally, in early 2010, his actions gave fruit. Five of the mappers have sent all game resources they still had to Leo and a remake is slowly in the works. The resources that have been salvaged, include: special PSX low resolution textures, some of which are unique, high resolution texture samples, several of the game's unique scripts by Nick Pelling and 'BAN' (including a weapon known as the Implant Gun, able to possess some of the enemies), and most importantly: almost complete set of maps, containing over 30 levels split into smaller segments due to PSX hardware limits. The mappers that worked on the PlayStation.

and here it is folks....... Converted to PC unreal and a standalone Unreal PSX Beta.
http://3dsl.game-host.org/shooter/game/5762

Hmm, after install, neither the Unreal.exe or UnrealEd.exe will run