Just tested myself and it seems like different browsers create different server profiles, meaning you can't start on Chrome and continue on Firefox - they will have separate individual save files. However, if you start on Firefox and continue playing on Firefox, the game should save fine. I just tested using the "Force Save" button in the settings menu, and didn't lose any data between play sessions. Regardless, I'll work on a fix for all of this in general, because it is not good that each browser is treating the game separately! Sorry for the inconvenience.
No saving, the developer's suggestions don't seem to work for me. Both the Force Save & Esc/Quit Game do absolutely nada... Too bad as that makes this game unplayable.
Really? Huh... I've never had any problem with it in my testing (using Chrome). I'll try on some other browsers. And you don't have the game open on multiple tabs, right? If it's open in multiple tabs/windows, the game will keep overwriting itself, so you'd lose data that way. But it should be fine if you only have it open in one location and use the "force save" button. Also, do you lose ALL of your progress when you exit? Or do you just get backtracked a bit each time?
 "Idle Hero TD"){kind=icon}
Just tested myself and it seems like different browsers create different server profiles, meaning you can't start on Chrome and continue on Firefox - they will have separate individual save files. However, if you start on Firefox and continue playing on Firefox, the game should save fine. I just tested using the "Force Save" button in the settings menu, and didn't lose any data between play sessions. Regardless, I'll work on a fix for all of this in general, because it is not good that each browser is treating the game separately! Sorry for the inconvenience.