UT_Codex is a community made map for GoldenEye: Source, and it is originally a level from the 1999 FPS Unreal Tournament. The layout is mostly untouched but small changes has been made to accommodate more balanced gameplay for Goldeneye's style of play and weapon and armor placement has been slightly altered to ensure optimal gameplay. The map was made from scratch in Hammer whilst using UnrealEd as a reference to ensure complete accuracy in scale, lighting and detail. A few props have been added to make the level feel less empty. Up to 16 players are supported.
The music packed along with the map are 4 songs from the original game, including the song that plays on the map in the original, Mission Landing. Version 2 was simply released to fix missing assets in 5.0 in order to be 100% compatible.