According to the game's composer Yuzo Koshiro on his Twitter account, he found an internal document for "Stage 7: Munitions Plant" from Streets of Rage 2 that revealed the stage used ideas from the manga series Akira, and particularly influenced the second half of the level which takes place on an elevator.
In the Marukatsu Megadrive interview, the game's composer Yuzo Koshiro was asked about what music influenced the game. He responded: "I started writing the music last Spring, which was right around the time The Orb was coming to Japan, and everyone (myself included) was super excited about that. I was listening to Prodigy and Eon too, stuff with weird lyrics."
Ayano Koshiro stated that she and her team love reading various of "Weekly Shounen Champion" manga, mainly "Baki" and "Apocalypse Zero" manga series. They were a big influence to the game and there were lots of mangas referenced in the game.
In the European version the main title has the same "Streets of Rage" title image used in the US version, but uses the roman numeral "II" similar to the Japanese title. The American release simply uses the number "2".
In the Japanese version Mr. X is seen smoking a cigar in the last level. This was censored in international releases.
Sound test track 10 on the ##Sega## Master System was intended to be the battle theme for Mr. X. But since there aren't any changes with the music in the area, Shiva's theme will be heard when they are about to fight.