- Several Newgrounds terms are used in the game's UI:
- The currency is "Grounds Gold".note
- Succeeding or failing in battle causes the results screen to declare that you "passed judgement"/were "blammed", respectively.note
- The screen before a stage denotes its flavor text with "Author's Comments".
- The game's main theme is a hard rock version of "Endless Handbag" — essentially Newgrounds' theme song, which played on its home page in its earlier incarnations.
Characters and Stages
- Fancy Pants Man uses a pencil as his weapon; in World 2 of his home series, he used one as a golf club. (In later games, he begins using it as a weapon, complete with many of his combos from Rumble.)
- The school stage has a poster reading "Apples and Bananas" - a reference to the beginning of Pico's School, where Pico's teacher has a lesson on the two.
- Darnell's presidency ad where he claims he has 5 years left to live also makes an appearance in the Pico's School stage.
- Tankman's "Gun" power-up move is riding a tank in the style of Newgrounds' logo.
- Both Pico and Nene's penultimate single player levels reenact Pico vs. Convict (the latter showing a different take on it).
- Samurai Asshole's Mighty Glacier status may come from the fact that his original game was rather slow and prone to lag (even by 1999 standards).
- Salad Fingers's Gun powerup has him bring out Hubert Cumberdale, who screams. Scratchy red lines appear around him, referencing the episode "Friends", when Salad Fingers hallucinates after cutting his finger and talks to a life-sized version of him.
- The Level 57 icon serves as the game's Invincibility Power-Up.
- The "Rage" power-up is Agnry Faic (an angry emoticon from Newgrounds' forums that took on a life of its own when it got two games of its own).
- Pico's ending reveals that he eventually dies of an unexpected fierce outbreak of herpes, "to which Nene claims no affiliation" - a reference to her initial appearance in Pico's School, where she visibly sports herpes sores around her mouth.
- Nene's ending (specifically, Convict impersonating her post-mortem) could also be a reference to Pico vs. Convict (which ends with Pico being forced to Spot the Imposter and accidentally shooting the real Nene).
- Tankman's ending references the then-impending massive redesign of Newgrounds (in-story, he demands the "nation" be redesigned), as well as an infamously terrible April Fools' joke related to it (long story short, they pretended to release the new design... but the only difference was the logo).