Cat: You realize you're going right into her trap.
Coraline Jones: They're my parents.
Cat: Challenge her, then! She has a *thing* for games. She won't be able to resist.
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.
When the other mother is making Coraline an omelet, pay attention. The egg yolk is in the shape of Jack Skellington's face. This is a reference to The Nightmare Before Christmas, another film directed by Henry Selick.