The project is a HD texture mod for the first part of the game series Thief: The Dark Project / Thief Gold.
These textures are almost completely not faintful to original, one way or another, so that pack (like most similar) rather ruins the athmosphere than improves the look of the game. If somebody is searching an eye-candy mod which stays true to the original design, I strongly recommend to pay attention on "Thief Enhancemet Pack" (for both thief II and I). There isn't the latest version on ModDB, next version is curretly on developing, but the latest stable releases (with recently imroved and updated textures) is available to download on ttlg forums.