Mararthon: Yuge is a 30 level scenario, plus 225 secret levels for many extra hours of gameplay.
Yuge is a community project that was created in 2017 with procedural level generation using rooms that were mapped by hand. Mappers contributed rooms of various design and size, which were then fed into the level generator, which created the overall level layouts, texturing, monster placements, items, and sounds. Therefore, you will see some of the same rooms multiple times while playing through the scenario, but each will likely have a different set of monsters in slightly different locations, different textures, and you will likely have different weapons.
The level generator was created by W'rkncacnter, and 353 unique mapped out areas were contributed by several mappers: Windbreaker, RyokoTK, Sankara, W'rkncacnter, President People, $lave, General Tacticus, Glamdring, and Adminn_1.
Yuge has 2 new weapons, 2 new boss monsters, new wall textures, new scenery objects, maps with precipitation, and a new liquid type. Along with the procedurally generated levels, the final level of the main scenario, "enter the DOUCHE", is a custom map created by Windbreaker.
Keep and eye out for a URL within the secret levels where you can download even more bonus maps.
If Simplici7y is up, look for the following files there to get better descriptions.