The main theme for "The Firefighter with Heroic Aspirations" sounds extremely similar to the main theme of the 1984 film, 'Ghostbusters'. The connection is likely a nod to the fact that the Ghostbusters' headquarters is located in a firehouse.

After footage of the game's final boss surfaced from pre-release copies, players expressed concern to the developers that some intense rapidly flashing lights and other visuals during the final boss may cause serious seizures to players that have photosensitive epilepsy, and in general may be an eyesore to players that are not epileptic. The developers understood and significantly changed the battle effects in a day-one patch that was heavily recommended by Square Enix to be downloaded by future players.

Several costumes featured in the game's announcement trailer have different names than they do in the final game:
• Tornado Wolf was "Whirling Wolf".
• Inky Blaster was "Cephalopainter".
• Water Blaster was "Super Streamer".

Each version of the game has a costume called the Launcher with a themed design unique to each console, though all variants of them perform the same ability of shooting bullets while standing still:

• Star Launcher is exclusive to the Nintendo Switch version and is red akin to the Nintendo logo. Its bullets feature star effects, likely in reference to the Mario series.
• Blue Launcher is exclusive to the PlayStation 4 and PlayStation 5 versions and visually resembles a PS5 console. Its bullets feature effects with the PlayStation face button symbols.
• X Launcher is exclusive to the Xbox One and Xbox Series X|S versions and prominently features the Xbox logo. Its bullets feature green X's similar to the Xbox logo.
• Steam Launcher is exclusive to the PC/Windows version and features a large red valve on its back, in reference to Steam's creator Valve. Its bullets are also valve shaped.

Each version's Launcher costume was originally unlocked if save data from the game's demo was detected, but since the demo is no longer downloadable, the costumes can now only be unlocked by inputting a specific code on the title screen: L, R, L, R, L, L, R, R, Up, Down. The official Balan Wonderworld Twitter account initially posted a hint for players to figure out the code themselves, which could be solved by identifying which costume is found in the applicable world number.