The developers really wanted a character from Square Enix's Final Fantasy series to make an appearance, but Square Enix refused to loan their characters due to SuperBot being a relatively new team and the game they were developing being relatively new as well.

Lara Croft was planned for the game, but Eidos declined on the grounds that they had different plans for the character and her Tomb Raider series at the time, presumably leading into the series' 2013 reboot.

Sony tried to obtain the rights to use characters and assets from Activision IPs in the game, such as Crash Bandicoot and Spyro, but negotiations fell through when Activision offered a hefty price tag for them.

Developer Omar Kendel stated that he was not a big fan of the game's much maligned Super-Move KO system, and said that if he could go back and redo it, he would.

PlayStation All-Stars Battle Royale was originally conceived as "Title Fight", a competitive multiplayer sidescrolling platformer type of game, but after the developers didn't jive too much with that idea it was instead turned into a competitive 4-player fighting game in the style of Super Smash Bros.

At the start of the planning phase of the game's development, Sony first went to their frequent collaborators, Naughty Dog, but they turned the project down due to wanting to commit their whole development time towards The Last of Us. Sony then approached many other of their studios, but all others were busy with other projects. So Sony had no choice but to create an original studio, SuperBot Entertainment, to fill the void.

The gargoyle in the background of the DLC stage, "Graveyard", will comment on characters that are participating in the battle.

Additionally, when talking about Nathan Drake, he will reference Tomb Raider by telling Drake that "these tombs have already been plenty raided".

Jak and Daxter's idle animation when not moving for a while will have them high five and then dance, as seen at the end of Jak and Daxter: The Precursor Legacy.

Sweet Bot, Sweet Tooth's Level 3, has a machine gun on its right arm. This is based on its concept for Twisted Metal (2012), where it originally had a machine gun, however, it was removed possibly to balance out the game.

In Jak & Daxter's ending, Daxter states, "I have a certain girl wearing a certain pair of pants i'm dying to see." This indicates that the game takes place after Daxter received his pants in Jak 3.
Even though Jak's unlockable costume is his racing outfit from the sequel, Jak X: Combat Racing, Daxter still doesn't wear his pants in this game.

Nathan Drake is the only character in the game to have intros and outros referencing other characters he is facing. For example, Nathan has an intro of him shown with a page from the Thievius Raccoonus, and he has an outro in which he tells Sully that he "punched a chicken", referring to Fat Princess's Level 2 Super.

Sackboy is much larger in this game; about as tall as PaRappa and Toro. In his own series, he and the other sack people are about 8cm tall.

According to Omar Kendall (lead game designer of PSASBR), at one point during development, Cole MacGrath and Evil Cole MacGrath were going to be one character, who would start out neutral, and turn good or evil based on the player's actions. After this idea was dropped, they decided to just use the Hero version of the character.

However, "the IP holders felt really strongly that the way that the Cole character manifests, he really is two different guys, and they felt the character would be best served as two different and they really pushed for it."

Dart from Legend of Dragoon and Abe from Oddworld were both originally planned to be released as DLC characters, but were ultimately cancelled. Concept art was made for Dart, and Abe was announced as cancelled DLC for April and May. Alongside the new characters, there were plans for a Gravity Rush/Journey stage, but it was also cancelled.

Sackboy's Pop-It is different from the one in the LittleBigPlanet series. This was done to integrate it into a fighting game as all of the icons represent moves done by Sackboy in the game.

PaRappa's Level 3 super is slightly different depending on the amount of opponents in the match. If there is 1 opponent, the U Rappin' Meter will raise to the "Good" level. If there are 2 or 3 opponents, the meter will raise to the "Cool" level.

Toro's three different "stances" are based around Street Fighter, Mortal Kombat, and Tekken. One of the moves he can use in his Torobi stance is inspired by Liu Kang's bicycle kick. In his Oni stance, he can throw a projectile similar to the mochi Hadoken.

PaRappa's intro and ending were made by the same company who did the PaRappa the Rapper anime.

Nariko, Sir Daniel and Jak are the only characters who's original voice actor did not reprise their roles in this game (though Jak and Nariko have their original voice actors in the Italian version).

Cole MacGrath, Emmett Graves, and Kratos are the only characters that have an alternate costume based on a different character. Cole's being Kessler, Kratos being Deimos, and Emmett Graves being Logan Graves.

The game 'PlayStation All-Stars Battle Royale' bears a very similar resemblance to the Super Smash Bros. series in gameplay, but the name also shares a similar resemblance in that the Japanese name for Super Smash Bros. is called 'Nintendo All-Star! Great Melee Smash Brothers.'

The moon in the background of the San Francisco level is the same moon that appears in the logo for Insomniac Games. Insomniac Games created both Resistance and Ratchet & Clank, the two franchises the stage was based on.

The boss "Polygon Man" was actually the Playstation's original mascot from 1995. He was meant to demonstrate the power of the Playstation, but was dropped shortly after the Playstation was announced.