Actor Allusion: At the start of Vs. Mode matches in the second game, Boxy Boy will quote Hairdresser Octopus for no real reason. Both characters are voiced by Freedom Bremner.
Bowdlerise: In the American version PaRappa 2, all instances of Guru Ant referring to himself as "the Lord" were changed to "the man", the lyric "...tastes better than wine" was changed to "...you better get in line", and "Warm the buns" became "Toast the buns" (to avoid Accidental Innuendo). However, they didn't seem to mind "Slurp it! Suck it! I know you all like it!"
The first game's gameplay had various concepts, One of them interestingly involved playing the guitar. This concept was later used in the game's spin-off Um Jammer Lammy.
Creator Killer: Greenblat's stress with working on the anime (in which he was character designer and had no creative input besides), combined with the fact that he felt that he was unable to come up with anything as successful as PaRappa, effectively drove him out of the video game industry (although he with Matsuura attempted a failed comeback with the 2009 flop Major Minor's Majestic March).