The game will attempt to autosave whenever you enter a new room. It's possible an anti-virus on your computer is blocking the function and causing the game to break. There is a potential work-around if you don't want to/don't know how to change your anti-virus settings. If you look inside the MAC folder there is a .swf version of the game. If you get the https://www.newgrounds.com/flash/player you can use it to open the .swf version and it should work just fine.