Aardman's first fully-CGI feature film. The reason for using computer animation instead of the studio's trademark clay animation was the large amount of scenes involving water, which is nearly impossible to do convincingly in stop motion.
At the beginning of the film, when Roddy is going through his wardrobe, the outfit he forgoes for the Elvis Presley-style rhinestone jumpsuit is a replica of the original Wolverine outfit from the comic books. Wolverine is another role that Hugh Jackman made famous.
When the stove falls through the floor of Rita's house, a cockroach that was sitting behind it can be seen holding a book. The book is Franz Kafka's novella 'Metamorphosis', the protagonist of which turns into a (non specified) insect, which is often translated as a cockroach. The cockroach appears to be reading a French translation: the title "La métamorphose" is clearly seen, while the Ka- in Kafka is obscured by the insect's 'hand'.
In the first theatrical trailer, Roddy was not the only pet of the little human girl. There was also a cage with two small yellow gerbils, who seemed to be Roddy's menservants. However, in the final cut of the film, these two characters were removed, probably to advance the story, and make Roddy appear to be a character who is more "alone" than "spoiled". The first trailer also shows the discovery of Sid during the day instead of late at night.
The books on Toad's shelf are "Warts and Peace" by Leo Toadstool, "Unfinished Verse" by Long Tung, "A Brief History of Slime," and his scrapbooks, "The Tragic History of the Great Great Toad, Vol. I," followed by Volumes II through VI.
The film uses software that was developed for the rabbits floating around the Bun-Vac 6000 in The Curse of the Were-Rabbit (2005). The software reproduces the 'imperfections' found in clay-mation (i.e. dropped frames, thumb-prints, etc.).
When Roddy and Rita are about to be 'iced' in the fridge, you can see that the controls panel the Toad is using is an early Atari 2600 game console (all the controls on the front). The game plugged into the unit is called "Froggie", a play on the old game "Frogger." When facing the Toad, the label on the back of the unit warns of "no service usable parts inside", and "opening the unit voids the warranty".
Bill Nighty and Andy Serkis, who portrayed Whitey and Spike respectively, also played motion captured villains in famous movie franchises. Serkis portrayed Gollum in the "Lord of the Rings" film franchise, while Nighty portrayed Davy Jones in the "Pirates of the Caribbean" film franchise.
When Roddy tells Rita that he will pay her in jewels, the script originally called for him lying about this. After rewrites, it was decided that he would be telling the truth, as him lying about this would be cliche.
The trivia item below may give away important plot points.
When Roddy gets flushed down the toilet, a fish gets thrown into his hands and says, "have you seen my dad." This is a reference the the Disney/Pixar movie Finding Nemo that came out 3 years before it.