Thanks for that update, even if I follow his progress from well known sources (most here didn't).
Not to deep into the Dev pit, but like you say, it's not that simple to start almost from scratch. Afaik, it might be easier to transfer from rpgm to renpy as from flash to unity.
Still a question I got in my mind: when we still are able to play flash Games, even if not supported anymore, is it still possible to work with flash? In theory, it's might be possible, even without further Updates (from Adobe).
Godot is a solid option besides Unity, the other game like Xeno Control have good animation going in there and similar to flash enough that i don't think it's a problem.
if the guy only specialized in Flash and doesn't want to learn new tech to kept his craft alive then this guy is wasted :I
and the problem with flash isn't really it's use but the scope of this game is too big to fit in flash.
and Scol animations called for better performance engine to work with even though he specialized in flash, it just doesn't cut it.
i used to dev some school project game and find anything to optimize and boost the performance as much as possible for a todler game, it's laggy af and always garanteed to have some kind of issue with big value and details that i don't want to dive into it.
at that time Unity is a better option but it just isn't good for 2D work and now with Godot around, the game could be really alive if he wish to continue it and actually finish a big project for once.
all in all just let the guy decide, i'm just sad that this game is wasted...