When the game was first publicly shown at E3 2004, it was presented as a conversion of Dōbutsu no Mori, Animal Crossing, and Dobutsu no Mori e+, differing mainly in the lack of acres and the use of the touch screen for chatting, designing patterns, and using the inventory. It wasn't until five months later that the game would take on the final product's front-facing style.

In the European release, the Mini Mustache accessory is altered from a toothbrush mustache to a pencil mustache. This change is most likely due to the toothbrush style's association with German dictator Adolf Hitler.

Within 14 review copies of Animal Crossing: Wild World (that had save data already on them) sent to media outlets to try out its compatibility with the then-upcoming Wii game Animal Crossing: City Folk, it was discovered that the villager Baabara's catchphrase "daahling" and the nickname she refers to the player as had been altered by an unknown party. The nickname was replaced with the colloquial ethnic slur "Ñiggá" with the first and last letters replaced with accented letters, and the catchphrase being replaced with the message "♥ u long time!!", a reference to a scene from the 1987 film "Full Metal Jacket".

Nintendo later put out a statement apologizing for the mistake and recalled the review copies, explaining that the game's wi-fi features (which allow catchphrases, appropriate or not, to be spread) were to blame:

Within the game's code are items colloquially known as "seeds" (their real names in the game's internal memory consist of garbled data) that spawn landscape objects (such as trees, rocks, or buildings) when dropped. The game uses these items to implement the layout of each randomly generated town.

Through cheating, it is possible to place these "seeds" in the player's inventory and spawn landscape features as they please, though they will not appear until the player has entered and exited a building. Placing these objects is irreversible, and it is possible to softlock or brick the game if they are dropped in excess or otherwise abused.

Ankha the cat was originally intended to appear in the game but was replaced by Anabelle the anteater for unknown reasons.

Nook's Cranny and Able Sisters are placed in a random location in a player's town, but always next to each other. However, the box art depicts them in separate locations.

One of the Messages of the Week can be "Bird, Bird, Bird. Bird is the word.", a reference to the song "Surfin' Bird" by The Trashmen.

During a Summer day, if you stand outside for 30 minutes or more you will get a tan. You can also get higher level tans the longer you stand outside. This can only be done from July 15th to September 16th and must be done on a clear day.

This game has a crash debugger triggered similarly to the one in Ocarina of Time. This one is a bit less technical and more informative, but a lot less in-depth. To access the crash dump screen, first crash the game; then, hold L, R, A, and Left, let go, hold Down and B, let go, and finally hold Start and Select. This screen also exists in Super Mario 64 DS and New Super Mario Bros.

Wearing the "Egyptian Look" set (the King Tut Mask and Egyptian Outfit) increases unluckiness for the player, making it more likely to trip and be stung by scorpions and tarantulas.