Yes, I exported my web version saves before it got turned off and I tried moving the files to my downloaded save files and it didn't work.
What is important is to get a file from that zip that is called something like 1-1-LT1.save (could be other numbers as well depending on the page and location it is on the save screen) and put it into the game/saves folder or AppData/Roaming/RenPy/MysticValley-1707149740 (if you're on windows, I don't know on linux or mac)