"The first version of the game, titled "NHL Hockey," was released in August 1991 for the Sega Genesis by Electronic Arts. It was developed by Park Place Productions, North America's largest independent development company owned by Michael Knox and Troy Lyndon. This version of NHL Hockey was also the first game to include the EA Sports logo. It was considered the most realistic hockey game of its time. The game used a vertical view, which was unique at the time since most previous hockey games used a horizontal or top-down view. It also features a National Hockey League license, so all of the team names and logos are used. However, lack of a license from the National Hockey League Players' Association NHLPA resulted in all players being referred to by their numbers rather than names. The Mega Drive version was released soon after, titled EA Hockey and featured international teams. However, this change is merely cosmetic, as most team colors could be tracked to NHL teams. Although the game has all of the NHL teams that existed at the time, the only competition present is the Playoffs, either decided in one or seven matches.
A component of the game which added to the game-play was the fact that fights would breakout in the event of a bad bodycheck. Players would fight with a computer player (or a friend in 2 player mode) which would go on until one fell down, ultimately losing the fight. During the fights the crowd would cheer and all other team mates and officials would stand by watching. After the fight was completed normal game play would resume. No advantage or disadvantage would be had from winning or losing a fight."
Source: Wikipedia, NHL Hockey , available under the CC-BY-SA License.