Playing via web Zeta directly on this page, restoring a save that I made puts me on the introductory text board with the marking squares controls and the hintbux counter visible, but the game is completely unresponsive outside of toggling sound, saving again (which restoring such a save simply puts me here again), or quitting.
Itch indicates that the page for the game was updated three hours ago, which is definitely after when my save was made. Did the update include changes to game files, and could that have broken my save? (Just to be clear, I have no problems with starting over.)