How hard would it be to add a puzzle editor? Then you could engage players into thinking puzzles for you and you could assemble next chapters out of best community puzzles.
Haha oh wow, that's interesting! Unfortunately as every puzzle is quite unique, it probably means exposing some scripting language to an editor. To be honest as this is a free game, and it was meant primarily as my foyer into game development, I wouldn't want to invest that much time into a "puzzle editor".