At around 6 minutes Vern opens the candy bar completely but right after he is shown eating the candy with the wrapper still on.
The sequence where the arrow pierces through the glass window without shattering it into pieces and hits Kathleen is an example of creative license. In reality, a glass window, especially tempered glass, would either break into small fragments or form cracks radiating from the point of impact, making the depicted clean penetration unrealistic.
At 1 hour and 55 seconds into the movie, Kathleen is hit by an arrow. Take note of the arrow: its feathers are blue and black, and the black tape is notably thick. However, 9 seconds later, the arrow is shown again with only black feathers and a thin line of tape, clearly indicating it is a completely different arrow.
When the father is on the couch, a crew member is visible in the window behind him.