There is a way to modify a save file instead of a workshop map, but it lacks features compared to the official map editor. If it is difficult to create a map, it is possible to create a random map with the map editor. TypeScript /** * The custom USGSOverlay object contains the USGS image, * the bounds of the image, and a reference to the map. Maps in the Steam Workshop require the map creator to share project files. I put some custom maps in that 'Maps'-directory and the game indeed also didn't recognize them and yes that folder has all permissions and this even occurs when running the game as administrator. You can start the game from there and play it normally to test the level. In the next screen you will find all the levels you have subscribed to STEAM, and all the levels inside the folder CustomLevels LOCAL. I had to make the 'Maps'-folder myself, but opening and saving a map in the worldbuilder also produced thiss map in the AppData directory. Affordable Google Maps alternative for Reverse Geocoding, Geocoding, Maps and Routing APIs. Then Start They Are Billions and, in the game main menu, go to: New > Custom Level. I can reproduce your issue, I also only saw those folders and the AdCache folder. Your first point won't help as you can't do anything with that file of course. Ahh, a nice custom map with lots of giants, which makes it more difficult than non giant filled maps, unfortunately.