It's thought that the four characters playable in the multi player and story mode games are based on four of the main Sonic The Hedgehog characters - Billy is Sonic, Chick Poacher is Tails, Bantam Scrambled is Knuckles and Rolly Roll is Amy. The Hatcher characters use similar colors and copy poses as well. For example, on the game's box art, Billy makes almost the exact same pose that Sonic makes on the cover art for Sonic Adventure 2: Battle.

As shown at the end of the credits, Giant Palace in its entirety, when viewed from above, is shaped like the Emblem of Courage.

According to former Sega of America product manager Mike Fischer, producer Yuji Naka originally wanted the game to be titled "Giant Eggs", but this was rejected by Sega of America as they were afraid that players would associate the title to the idiom of "laying an egg", or failing. One team member suggested naming the game after the main protagonist "Billy Hatcher" to fit with the theme of hatching eggs, but Naka reportedly hated this name. At one point during one of his American visits, Naka instead proposed to call the game "Giant Cock" in English, in reference to Billy Hatcher wearing a rooster costume, and "cock" being another word for a rooster; this was also rejected for being an explicit double entendre. They would ultimately compromise on the title "Billy Hatcher and the Giant Egg", though Fischer notes that Naka hated this name as well. He concluded by calling Naka "literally the most miserable person I have ever worked with in games or anything else in my life, just a horrible human being, and you can quote me on that."