Other mistake: When Heather Hills takes a swing at Rodrick with mike stand and hits the chocolate fountain, how does Heather splash chocolate on herself?
Plot hole: When Greg gets caught faking his summer job, the receptionist tells his father that they don't employ minors, but Heather Hills who is sixteen (we know this because she is about to have her sweet sixteen) is a lifeguard at the pool.
Character mistake: When Greg reads the article about L'il Cutie being cancelled, cartoonist is misspelled cartoonish. The article also repeats the first column word for word in the third column.
Factual error: When the boys get off the cranium shaker about ten people follow them out of the exit gate The ride only seats four.
Continuity mistake: In the scene where Greg and Rowleys family are playing the game "I love you because..." the spinner they use keeps on changing positions in between shots. (00:42:00)
Character mistake: When Greg notices his yearbook picture, the pictures of each student are in alphabetical order by last name. On the row Greg is on, the order is mixed up; The order is: Holly Hills, Wes Hamby, Greg Heffley, Rowley Jefferson. The order should have been Wes Hamby, Greg Heffley, Holly Hills, Rowley Jefferson.
Continuity mistake: The time on the cranium shaker changes dramatically from 5 minute wait to when the boys get on and to 1 hour 10 minutes when they get off a few minutes later.