Guten Tag! is a map set for shareware Wolfenstein made by Thomas Weiling. It was released on December 16, 2012.
Thomas had begun making levels for a possible Lost Episodes map set in the fall of 2012, but eventually found the atmosphere difficult to work with. Not one for having stuff sitting on the shelf, he redesigned the levels to fit shareware Wolfenstein 3D, and created a quick boss level to get the set released quicker.