One bug I ran into: I was in the middle of my first encounter with the squirrel thing (sorry I forgot its name) and I had to go do something, so I exited out of the game via the x button, since I can't leave mid-battle, and when I started the game up again, it loaded fine but I couldn't progress through the demo any further since the squirrel was gone. Also, the quit button wasn't working.
Update: Is the quit button's purpose to exit the menu? If so, that makes way more sense.