The game negates the browser's zoom settings actively in order to achieve pixel-perfect text, so changing it wouldn't help.
A few questions:
- Do you play in windowed mode or fullscreen? If fullscreen, is it activated in the game (Options > Fullscreen) or by the browser (F11 or View > Full Screen)?
- Do you get the same issue when playing the Intro here on itch.io? Normally, you should see "Done" and "Skip" buttons on the top-right and bottom-right corners.
- In about:config, has any of the following settings been modified (appear in bold): layout.css.devPixelsPerPx, layout.css.dpi, privacy.resistFingerprinting ?
- Most importantly, do you currently have any workaround?