When Gigan is defeated, his head will explode, as it did in Godzilla: Final Wars.
There is an unused sound file in the PS3 version of the game of the G-Force operator saying Mecha-King Ghidorah's name, suggesting that he was going to appear in the game but was scrapped. However, Mecha-King Ghidorah was later added to the PlayStation 4 version of the game
In an interview with Shunsuke Fujita, the game's producer, he mentioned that at first he didn't even intend for Jet Jaguar to appear in the game, but walked into his office and saw him on the screen, and "couldn't say no." In this same spirit, Fujita said that he would consider adding any available monster to the game, including Godzooky. In the same interview, Fujita stated that the reason he made Godzilla move so slowly in the game was so that it didn't feel like the 1998 film.
In North America, pre-ordering the game earns players instant access to Hollywood Godzilla as a playable monster, a special game mode called "Showa Mode" which makes the game appear like the 1954 film, and a free Godzilla: The Game poster.
If the player encounters Jet Jaguar three times in one playthrough, after defeating him the third time the player will obtain a trophy called "Our Jet Jaguar" and a cutscene will be triggered showing Godzilla and Jet Jaguar shaking hands as they did at the end of Godzilla vs. Megalon.