Revealing mistake: In the scene where Violet sings for Kevin for the first time, he starts to switch the lights off. Notice when he has turned off the lamps, the room is still very bright, but when he blows the candle out, the room is suddenly totally dark. That single candle could not possibly have lit-up the room and the characters the way it did, after the electrical light was switched off.
Revealing mistake: In the scene where Violet writes "Right Kind of Wrong," she plays the first two chords of the song backwards on the keyboard. The chords in the song go from a higher chord to a lower chord, and she plays as if it was the other way, moving her right hand from the lower notes to the higher notes on the keyboard.