World Heroes is a series of fighting games created by ADK originally created for the Neo Geo MVS arcade cabinets with the assistance of SNK, though some of the games in the series were also ported to the Neo Geo AES and Neo-Geo CD platforms, as well as some non-SNK platforms such as the Super NES and the Sega Saturn.
While it was created during the years when Street Fighter II was at its peak in popularity, many dismissed World Heroes as another generic "SF clone." Though it has some unique concepts, the controls being considered clunky and its "ripoff" reputation harmed sales. Due to this, the series was discontinued with World Heroes Perfect, although it has received a cult following mainly around Neo Geo fans.
The general premise is that a scientist, Dr. Brown, having perfected a time machine, organized a tournament for various fighters throughout all of history to combat each other. True to this plot, many of the fighters are based on actual historical figures.
Source: Wikipedia, "World Heroes (series)," available under the CC-BY-SA License.