We learned that Dudley has ended school five years ago, which could give a hint to Dudley's age.
He could be apparently 24 or 25 years.
This is the first appearance of the Petropolis Rain Forest.
There are species in the rain forest like the Venus Cat-trap (parody of Venus Flytrap), the Poisonous Moth Bush, the Dorchid, and UUUGH (a monster that Dudley manages to communicate to rescue him and Kitty).
This is the second time that Kitty wears makeup (apparently). The first was in Freaky Spy Day.
This is the second time you see another blue-bottomed booby besides Bird Brain. The first time was in Booby Trap.