I agree, but AFAIK all those games leverage GML rather than just using the Game Maker UI. That's definitely the case for Derek Yu's games. I corrected myself in a further comment in this thread, but I meant to refer to the sort of basic interface with which you are encouraged to interact with at first. GML is great, but most game maker newbies won't be devling into it until they run into a brick wall for UI action components (probably an array based brick wall, if my experience is anything to go by).