When the snow blows in through the window and covers Barney, the camera moves in on him closer and the amount of snow on his bed's headboard suddenly changes. Clarification: As the camera zooms in, the snow on the headboard and behind Barney disappears briefly then reappears.
The teakettle that Barney uses whistles, but the style of the kettle does not have a whistle in it, so it shouldn't whistle.
Barney has 10 locks and a huge log to secure his front door but only a single rickety latch to keep his window shutters closed.