Ha — you're right that the save's just sitting in localStorage to poke at. For a hacking game I'll take that as on-brand. 🙃
The localStorage.clear() returning "undefined" is actually normal — clear() just returns nothing, so that means it ran. The reason your progress survived: on itch the game runs in an iframe, so the console executed against itch's page, not the game's frame (different storage bucket). Switch the console's context to the game iframe (frame dropdown at the top of the Console tab), or run it on a downloaded copy, and it'll wipe.
