A jumping ship shouldn’t happen. Hm. Except directly after clicking (because the script has to evaluate to compute the new position).
I was experimenting with a new way to store state in this entry because the last game jams I participated in made me realise that HTML-based games are restricted by the iframe they’re loaded in. Here I put the state basically in the URL (which isn’t exposed in the browser but can be modified in the DevTools). Like, you know, push the boundaries.
I even wrote itch Support in the beginning of March to be more detailed in their documentation but never got a reply.
Have you seen the comments on the game page?