An early title screen in the game data suggests the game's original title was "Nickelodeon All-Star Brawl Universe". For unknown reasons, the "Universe" part was dropped.
Contributed by PirateGoofy
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Previews for new fighters being added to the game showed that one of Jenny's intended pre-battle quotes was "You wouldn't like my brain! It's all circuity and metallic!" This was removed from the final game due to it being associated with a pornographic My Life as a Teenage Robot parody animation, which edited the line to replace "brain" with "body."

Thaddeus Crews, a member of the development team, initially expressed disgust in a now-deleted tweet (the tweet he replied to also having been deleted) that the line was in the game and announced its immediate removal. He later explained that the line was likely added due to a lack of awareness about the parody, the end result of the team being "spread out and not on the same page", while adding that "Most likely someone on the team did know what they were doing by adding it", despite Crews himself being previously aware of and publicly associating the original line with the porn parody prior to its removal from the game.
Contributed by game4brains