Beautiful little game, taking notes from Miazaki I take it :) ? I don't think I figure it out, tho, only found the watering pot and explored all 4 areas before I got the black screen crash.
Also, I played it late at night and at first thought it was tied to my real clock thinking "oh neat, so I gotta play it at different times!" Was a little disappointed that wasn't the case. Maybe food for thought?
Do you mind me asking how you did the escape menu? Just render to texture camera on the entrance and teleporting player to actual location? and what about your lighting - just toon shader with a non-gradient black/white ramp texture?