Continuity mistake: During the other father's song, notice the red record player by the door and the position it's in, with the lid facing Coraline when he says, "making up a song". When the camera angle changes and he says, "she's a doll", the record player's position changes completely, with the lid now facing the wall.
Continuity mistake: During Coraline's first meal with her Other Mother and Father, just before Coraline says "I'm real thirsty." there are two drinking glasses to her right, the one she uses a couple seconds later and a smaller one. After the cut to the chandelier lowering, it goes back to Coraline and the smaller glass has completely vanished.
Continuity mistake: When Coraline is in bed in the other world for the first time, she's holding the picture frame showing her friends face down. When the shot changes to her again, the frame is facing up. (00:21:35)
Continuity mistake: In the scene of Coraline's first dinner in the other world with the other parents, you notice the small water glass is full. Later, when Coraline says, "I'm real thirsty" there is a substantially smaller amount visible.
Continuity mistake: When Coraline goes to see her father for the first time in his study, there are three boxes at the entrance. She enters, puts the Coraline doll down on the smallest box with the doll's legs and right arm hanging down, then she starts playing with the creaky door. When her father tells her to stop, the boxes have changed position and the doll's legs and arm are straight. (00:10:05)
Trivia: The blossoms on the trees are actually painted popcorn pieces. The crew spent over 800 hours painting 250,000 of them. (Source: Wired magazine).
Answer: Opinion is divided - it's either Coraline's face, or the other mother. No-one seems able to decide which.