TTG corrupt?

I played TTG from this site over the last two days. When I came to Ghost Island it suddenly lost most graphics. I uninstalled and reinstalled (but I think that was just the shortcut? Am I actually playing it directly from this platform here?) I was then able to replay Ghost successfully but the game doesn't think I finished that island because when I go back to it, it's starting over. The same thing happened with dreams of ruined shores. And now i see Scorched also doesn't act like I completed it, which I did. I keep uninstalling but that makes no difference. Please help because I cannot proceed in game to pyramid or gazing etc.

I did get to Gazing Canyon after all but it also is not showing complete and is giving me just one of the Magi seals even though I opened both chests.  I also am not getting all the feathers into the inventory even though I have double checked I picked up all 8 feathers. This game is going to be impossible to complete. Is it because I am running on Windows 11? Please fix.