Just wanna add that Fusion is also the most easiest to use out the other programs that I have tried.
God knows how many years ago when I wanted to try to do something game dev related with 0 knowledge I tried RPG Maker, then I tried GM 4.0-8.0.
But the UI and how to make anything whatsoever was too painfully confusing for me.
Later saw Unity, Unreal and GM Studio... Nope wanted none of that either.
But Fusion somehow instantly clicked with me, like I could figure almost everything out on my own, mostly simple and can just test any part of the game with 1 click of a button no extra hassle and virtually do anything I want outside of some super complex stuff that needs figuring out.
Now is it perfect? Ofc not none of the game making programs are.
But generally speaking Sonic was always Fusion first, GM4.0-8.0 second "Now being GM Studio"
And rest is just whatever people wanna make their "3D" engines on.