Aardman's first fully-CGI feature film. The reason for using computer animation, instead of the studio's trademark clay animation, was the numerous 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 the role that made Hugh Jackman famous.
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 manservants. 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.
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".
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 claymation (for example, dropped frames, thumbprints, et cetera).
When Roddy (Hugh Jackman) and Rita (Kate Winslet) are about to be "iced" in the fridge, you can see that the control panel The Toad (Sir Ian McKellen) 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".
Once Roddy enters the sewer version of London, a female mouse shouts "Feed the flies, tuppence a bag!" This is a reference to Mary Poppins (1964), set in London, where it's "feed the birds, tuppence a bag!"
At the beginning, Roddy puts on a movie called Die Again Tomorrow. This pays homage to the Bond movies Die Another Day and Tomorrow Never Dies (1997). The cover nods to Goldfinger (1964), and Roddy recreates the gun-barrel from the start of each Bond film.
Bill Nighy and Andy Serkis, who portrayed Whitey and Spike respectively, also played motion captured villains in famous movie franchises. Serkis portrayed Gollum in The Hobbit and The Lord of the Rings film franchises, while Nighy 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 re-writes, it was decided that he would be telling the truth, as him lying about this would be cliché.