So did I, which was what gave me the idea to make this one :)
My original plan was to charge for it, but all my first drafts kept accidentally being way too close to what's actually in Deltarune and I felt like it was too much of a legal risk (I don't want to get run over by a dog in a toy car in a dark alley...). Also a pretty sizeable part of the fanbase is too young to be able to buy stuff online, and that would exclude them from the engine, which felt counterproductive.