A sequel was in the works but cancelled when the actors who play the protagonists underwent a major growth spurt suddenly.

At Heather Hills' Sweet 16 party, during LD's performance, Heather Hills swings at Rodrick with his mic stand, missing him, but in turn knocks her chocolate fountain over & away from her. In the next shot, she's seen standing next to her friend on the opposite side of the fountain, without the mic stand, & the chocolate fountain has been splattered onto her somehow.

The animated 20th Century Fox logo at the beginning of the movie changes to a cartoonified version, and a beach ball flies across the logo.

Edited from Diary of a Wimpy Kid (2010)