None yet, will try to remember not to clear cookies :) Sometimes games that don't maintain user accounts let you save progress in a file and restore it later, so that it survives loss of browser state, see e.g. https://microcorruption.com/

Thank you for the game by the way! It's nice to recall my asic classes, and looking forward to GPU specific chapters.

Oh, no, now I actually lost part of my progress. Apparently has something to do with multiple tabs open.