I made sure to hit save and then exit to main menu, minimized window until next day. I open it up (it didn't even reload the page) and my data is gone. The only reason I did this, is because when I shut my laptop overnight, it didn't keep the time running. 3 days and it said I was only on for 22 hours and my storage wouldn't fill so having the manager was useless. slowed down with golum, but broken robot really dragged. Thought once I hit the lost city it would really get fun again but just not enough.
TL:DR: Three hundred thirty something level, don't trust the save, you'll lose it.