River City Ransom is an English localization of the Family Computer video game Downtown Nekketsu Monogatari, which is the third title starring Technōs Japan's mascot character Kunio, who previously appeared in Nekketsu Kōha Kunio-kun and Nekketsu Kōkō Dodgeball Bu (the Japanese versions of Renegade and Super Dodge Ball respectively). This is the first game in the series where Kunio teams up with his rival Riki, who fought against Kunio in the previous games. The gangs the players fight in the Famicom version are all students from different high schools and many of the characters introduced in this game would reappear in subsequent Kunio-kun games (particularly those that were directed by Sekimoto and Yoshida).

In addition to anglicizing all of the characters' and locations' names, as well as the game's dialog in the English translation, the characters' sprites were also redrawn, replacing their Japanese school uniforms with t-shirts and jeans. The number of difficulty settings was reduced from three to two (the easiest difficulty setting was removed and the Medium setting in the Famicom version became the Novice setting in the NES version) and an alternate 2-player mode (2P Play B) which disables player-against-player damage was removed too. In addition to a Password feature, the Japanese version also features support for the Turbo File, a peripheral released only in Japan that allows the player to save and load game data.

River City Ransom was the first console game localized by Technōs Japan's U.S. subsidiary, American Technos Inc. Although most of Technōs Japan's previous games (such as Renegade and Double Dragon) were released in North America as well, they were licensed out to other publishers. The second and final NES game released by American Technos was Crash 'n the Boys: Street Challenge, which was also a Kunio-kun game.

X68000

Downtown Nekketsu Monogatari was ported to the Sharp X68000, a Japanese computer platform, and released in April 1990. This version of the game, which was developed by SPS and published by Sharp, features several enhancements to the Famicom original, such as displaying three enemy characters on-screen instead of just two, slightly more colorful graphics, an expanded game world, and new items and special techniques for the player (including some that were only used by certain enemy characters in the Famicom version, such as the headbutt and the whirlwind kick). The new locations includes several new shops (such as a dojo) and the schools of each enemy gang, each featuring two new bosses. In addition to the player's regular stats, the player also has individual stats for all the special techniques their character has acquired. The more frequently a special move is used to finish off enemies, the stronger that particular move becomes. Unlike the Famicom version, the X68000 does not feature adjustable difficulty settings. The player can save and load their progress in one of ten save files provided by the game itself.

PC Engine

The PC Engine Super CD-ROM² version of Downtown Nekketsu Monogatari, released on December 24, 1993, was published by Naxat Soft and developed by KID, the same team that did the PC Engine versions of Nekketsu Kōkō Dodgeball (Super Dodge Ball), Double Dragon II: The Revenge, and Downtown Nekketsu Kōshinkyoku. This version features enhanced graphics, an arranged redbook soundtrack and fully voiced characters, with the voices of Kunio and Riki performed by Ryō Horikawa and Nobutoshi Canna respectively. The player's progress is saved in this version on the PC Engine's backup memory. The rest of the game is almost identical to the Famicom version.

Game Boy Advance

A GBA version of the game, titled River City Ransom EX (ダウンタウン熱血物語ex, Downtown Nekketsu Monogatari ex) was released in Japan on March 5, 2004 and in North America on May 26, 2004. This remake was developed by Million and published by Atlus. The most notable change from the original version is the loss of a true cooperative mode. Instead, the game can be played with an AI-controlled partner, and players may exchange the data of their own characters to fight alongside each other. The GBA version also includes a vast amount of configurable options that can adjust game play on the fly, such as changing AI behaviour, the amount of enemies in one map area, and shop item reshuffling frequency. The password system is replaced by battery backup, which allows saving up to 12 characters. Character's appearances, keystrokes for learned techniques, even enemy characters can be customized and saved using secret shop items. A saved game does not store story progress or reputation, but it does store the player's statistics, techniques, current items and money, player's name, and customized appearances. The player can gain additional computer-controlled allies and form a "posse" who helps the player on his adventure. Some of these are boss characters from the original NES version, while others are taken from later Downtown Nekketsu games. The player can be accompanied by up to three AI-controlled partners.

Wii

The original NES version of River City Ransom was re-released on the Wii's Virtual Console service in Japan on October 23, 2007, in PAL regions on February 21, 2008, and in North America on April 21, 2008. The western NES titles, graphics, and storylines for the latter two releases were left intact.

The Japanese version, Downtown Nekketsu Monogatari, was considered highly successful and would be followed by several spinoffs (including seven subsequent Famicom installments) until Technos Japan's closure in 1996. Of these seven games, Downtown Special: Kunio-kun no Jidaigeki dayo Zen'in Shugo features the same gameplay system as Monogatari, with the main difference being that the characters are re-enacting a jidaigeki play.

Outside Japan, River City Ransom was not highly successful when initially released. However, due to its unique gameplay and sense of humor, it is today considered a cult classic. This cult following, combined with the game's character and humor, inspired parallel works.

In 2002, an aspiring game designer, tester for Atari, and longtime fan of the game obtained the title's trademark and began work on a sequel aptly titled River City Ransom 2. The project was halted when it was announced at the Electronic Entertainment Expo in 2003 that River City Ransom EX was to be released the following year. However, a true sequel to the game was announced on March 18, 2011. Downtown Nekketsu Monogatari 2 (ダウンタウン熱血物語2) is being developed by Miracle Kidz for a Japanese release on WiiWare in 2011. An online PC version was due out in 2012. On October 22, 2012; however, the game was on hold due to the development is frozen and focus on making completely original games.

Retro City Rampage is also highly influenced by River City Ransom and pays homage to the game.