In the Japanese version, by pressing A,B,C,A,B,C,A,B,C in rapid succession on the Options screen, an easy mode will be unlocked. The game will be significantly easier, but the first level of the game will change to a light and cheery aesthetic instead of the dark and moody one of other difficulties.

At the north end of the Bridge map, using the "Kangaroo on Command" power up will allow the player to scale the rock wall border of the map and enter a secret room. Upon entering the room, a message will state "Friggin Kangaroo on Command freak." Turning around from that message will show another large message that says "Now you are stuck SUCKER" and create an invisible wall that will trap the player in the secret tunnel.

If the game detects a pirated copy, this message will appear upon booting up:

ALERT!!!

Pirated Copy!

But you're in luck. For
just $32.50 you can get
your own, unpirated copy
of 3-K Trivia!

Unused Paintinator models and icon can be found in the data.

In Route C, if the player talks to Jackass after the bunker's destruction, she'll comment that she had a friend on The Bunker named "White." This friend is revealed to be The Commander in the Black Box Edition Art Book.

In the RC Car play section, the numbers 1889 and 2018 can be found under the cover of the controls. "2018" represents the year that Nintendo Labo released and "1889" refers to the year that Nintendo started as a company.

Once you've finished the game and return to the main menu, Spoiler: when Chloe, the android who serves as a guide, asks you if she could be set free, it was originally intended that she'd permanently disappear if the player lets her go. However due to player requests, in an update it was made that if the player had let her go, they could later be asked if they wanted another Chloe android to take her place.

During the Rupert the Gunsmith sub-mission, a pink teddy bear can be found in Rupert's apartment. Activating this bear will make it say "I love you.". As the player continues to activate this bear, the bear's dialogue will change, and it will insist you stop touching it. If you proceed to activate it after this warning, its eyes will turn red, and the bear will explode.

Super Smash Bros. Ultimate is the first game in the series that requires players to select a stage before selecting a character in multiplayer matches. In previous entries, as is common in other fighting games, it was the opposite. This is an attempt by Masahiro Sakurai to change up the strategy of the game (specifically stage-character match-ups).

The cartridge label of the NES game Ice Climber found in the game's main treasures differs in it's appearance depending on what version is being played. In the japanese version it uses the Famicom appearance and artwork, whilst in the western version it uses the NES appearance and artwork.

There is code from Battlezone II: Combat Commander, another game developed by Pandemic Studios, left in the GameCube version's files.

According to Tetsuya Nomura, the aesthetic and environment design for part of the Hercules-based "Olympus" world was primarily inspired by California's Yosemite National Park, despite, story-wise, taking place in Ancient Greece. This decision came about when co-director Tai Yasue had visited the real-world location.

In the Wii version’s files is an unused animated version of the EA Sports logo. The final game uses a stationary one.

When Miis speak the word "Direct", they'll do the pose that Satoru Iwata was known for having done in Nintendo Directs when saying "Directly".

Solid Snake's series logo was changed from the FOX emblem that was used in Super Smash Bros. Brawl, to the exclamation point seen when being caught in most Metal Gear Solid games.

This is likely because the FOX emblem (which first appeared in Metal Gear Solid 3: Snake Eater) is also commonly associated with series creator Hideo Kojima and his company Kojima Productions, a former subsidiary of Konami. Kojima left Konami in 2015 and the removal of the FOX emblem to represent the series is likely a biproduct of the split.

Two giant fruits can be found in hidden rooms during the game. A giant apple can be found in Chapter 7 at the bottom of the spiral staircase in the Tower of London. The second, a giant banana, is found at the start of the final chapter behind a door.

Two unused maps can still be found in the game's data. One is a pirate ship and the other is a round room with four doors.

Very early on in the game, if the player makes certain unorthodox decisions in the Kara storylineSpoiler: it is possible to have both Kara and Alice die extremely early. If the player goes to the Main Menu right after doing so, Chloe will slightly break the fourth wall and scold the player for "letting them die". She will then tell the player that the "lives of these androids are in your hands".

In the PS2, GameCube, Xbox, and PC version's files are removed game modes. These modes include Tournament, Burnout, Knockout, Car Show, and an otherwise undefined "GT" mode that hadn't appeared in previous entries.