- Colbert Bump: The franchise as a whole is gaining one thanks to River City Girls reaching a much larger audience than the relatively niche installments. Being co-developed by popular game-developer WayForward Technologies helps.
- Divorced Installment:
- Renegade was so popular in Europe that the British company Imagine Software developed two direct sequels to this version: Target Renegade and Renegade III: The Final Chapter.
- River City Ransom: Underground takes place in the American urban setting created for the English localization of River City Ransom. Barring a couple of homages, there's little trace of Kunio-kun references to be found.
- Dolled-Up Installment: The 1990 Game Boy entry, Nekketsu Kōha Kunio-kun: Bangai Rantō Hen, was remade into a Double Dragon game, probably for brand recognition. It's confusingly named "Double Dragon II", even though the gameplay is identical to the Japanese one and, as such, has nothing to do with the Arcade and NES game of the same name.
- No Export for You: Most of the series remained in Japan. Kunio-kun: The World Classics Collection brought most of the games together in one collection, in Japan.
- Averted with the Famicom games because of DOUBLE DRAGON & Kunio-kun Retro Brawler Bundle which not only brought every Kunio-kun game on the Famicom officially to international audiences but localized all of them in English including giving more accurate localizations to the games already released in English.
- What Could Have Been: As seen at the end of Crash 'n the Boys, Nekketsu Hockey Bu was planned to be released outside of Japan as Crash 'n the Boys: Ice Challenge, but this never made it to the US as the NES was unfortunately approaching the end of its lifespan.
- Wiki Rule: There is a wiki for the series here.
Trivia / Kunio-kun