We apologize for our misunderstanding. We have been able to successfully reproduce the presented issue and we are looking into ways to fix it.
There is currently a workaround for this issue, where if you create a folder named “www” containing another folder named “save” in the directory where you have downloaded the game, you will be able to save the sessions normally.
We are sorry for this inconvenience. We will continue to do our best to make sure such issues will no longer occur on your end.