I dont know what the hell is construct 3 can you explain that. And as for steam its super easy. Devs simply need to add mode support and open steam workshop. Done. Hell you dont even need steam to add mods you can just add mode support to the game (same as steam) and let others from anywhere anyone mod it. From itch io, steam, f95zone anywhere. New models, new voices, new text message, hell even a new story, extra story, new scenes anything becomes possible with mod support just look at L4D2.