CORS errors and redactor errors are from itch.io itself, I've seen those ones and unfortunately I'm unable to do anything about it. Luckily those don't affect the game's operation in any way.
The searches for 'unlocks' and 'attack_cooldown' in undefined are attempts to find the player, which is interesting since they're defined earlier in the same file. I kick off the tick and animation loop from onLoad so that race condition shouldn't happen, but that's programming for you!
The one cause I can think of is broken save data. If you're using firefox, in the "Storage" tab, under "LocalStorage", you'll see a line item for the cdn, and the save is kept under "save" in there. Deleting that and reloading the page will sweep away the old data and give you a fresh start. I'll put in some more defensive code too in case we see this again.