Downtown Nekketsu Monogatari (known as River City Ransom in the west) is a port of Technos's beloved NES brawler/RPG. Its gameplay is nearly identical to the original, and features two-player brawling in an open world where you collect coins from defeated enemies to buy food to upgrade your stats. It also features a remixed CD-quality OST.
Like Double Dragon II on the PC Engine, this port was developed by Kid rather than Technos.
This is the only version of River City Ransom not available in the US.
The PC Engine port of Downtown Nekketsu Monogatari (aka River City Ransom) is pretty much exactly what you'd expect. It plays identically to the NES version but updates the graphics and sound. If you're a RCR maniac, you'll probably get a kick out of this, but if you've played the original you've essentially already played this version.