Metal TC was a project for Wolfenstein 3D, made by Mäx. Initially announced via a bulk update on various projects in October 2006, some screenshots were released but no actual product ever came out.
The mod may have been a forerunner to Northern Darkness, in that the protagonist is the same. As evidenced by the screenshot, the mod alludes to the heavy metal scene and its various subgenres, ripe with creative new graphics.