Continuity mistake: While Stewie and Olivia are performing, Olivia is wearing a light purple dress. After the performance, when Stewie and Olivia are sitting on the piano talking to their teacher, Olivia's dress changes from purple to blue in between shots. She is also wearing dark red lipstick instead of none at all.
Revealing mistake: After the fight between Stewie and Olivia at the concert hall (followed by their breakup), Simon tells Stewie that the act without Olivia is "over" as he turns to walk off the screen. However, before Simon is even partially out of the shot, he completely disappears.
Continuity mistake: When Simon is working with Stewie in his "The Life Cycle" exercise, there are three children behind him: a redhead with freckles, a blonde with glasses, and another blonde. However, after Simon turns around and says, "Any comments?", there is a wide pan of the kids in the class, and the three kids have completely disappeared.
Continuity mistake: When we first see the sign outside the Quahog institute of performing arts, it has a cartoon take on the comedy and tragedy masks in the corners. In the left hand corner is a black mask with big ears and a smile and on the right is a white mask with a frown. Later on, the black mask has the frown and the white mask has the big ears and smile and the 3rd time you see the sign it has changed back again.