I've spent the last hours looking into this, but unfortunately I was not able to find a satisfying solution. The autosave is writing around 400 characters to the cookies every second, which shouldn't really cause problems under normal conditions.
Many browsers allow you to run some code before a window is closed, unfortunately they don't allow enough time to actually save anything. As a result the only way I can ensure progress is not lost, is to autosave frequently.
....dont save the game ever second. once per minute is more than frequent enough, but saving every single second is just going to damage peoples hardware from unnecessarily frequent writing. and again, for some reason your game is EXTREMELY hard on HDDs. like my drive isnt even that loud when im rebooting, and doing heavy reading/writing from it. i get that youre not sure why, but its something you really need to look into.
I didn't get notified of these new messages, just saw them.
To ensure that nobody's drive is getting more wear than necessary, I've changed the autosave to happen every 60 seconds instead. After investigating it, there doesn't seem to be a consensus whether or not frequent reading and writing wears down drives. I will use a similar autosave interval for future games, and let the player manually save as well, to ensure a good user experience.
A differential save wouldn't really make a difference, the save file is already miniscule as is and only uses a tiny fraction of a percentage of what a drive is capable of in terms of data throughput. I speculate spinning up and down is what is making the sounds.
