So the dude threw it up onto Steam with literally NO thought given to making the save import work.
That SUCKS.
Viewing post in Smashing Simulator Idle comments
The Steam version imports save data from the clipboard and doesn't pay attention to whatever save file you currently have. It worked for tableclown because they copied the data before clicking import. The only other issue people had was that the text editor was laggy when viewing the data, for which I'm about to push an update to decrease the save size, though that'll only work for the Steam version. Besides that, it works fine.