Actually twenty maps, and just as interesting as the levels themselves is Clubey's admission that he slightly modifies certain maps beore release.
The second and last compilation is called Compilation des 21 niveaux, which reportedly means "compilation of 21 levels" when translated from French. It was made by Jean-Sebastien Rimmel. True to its name, it offers 20 maps for the Third Encounter (although I only see First Encounter enemies used). Those maps are nothing out of the ordinary, many being just a bunch of mostly rectangular rooms with a lot of enemies, although they significantly grow in size and complexity in the last five. A potentially more interesting thing can be found in Clubey's readme: he says he modified these maps slightly, removing the items automatically placed by WolfEdit in the bottom right corner (many modders leave those intact for some reason) and placing crowns and secret pushwalls near the exit elevators as needed. I've seen a bunch of maps before where the only treasure item was a crown or one-up right in the exit elevator, so it's interesting to learn that it might have been Clubey's work. And as a community maintainer, Clubey isn't unique in his desire to improve releases: as far as I know, Brian Lowe (the owner of Wolfenstein 3D Dome and some other websites) also slightly modified certain releases before placing them for download. Personally I would have left them untouched, but I guess either approach has its pros and cons.
===CREDITS===
Jean-Sebastien Rimmel.