as an option. Wizard of Wor offered solo, competitive two-player, or cooperative two-player gaming. while Williams Electronics' Joust encouraged players to alternatively compete and cooperate by awarding bonus points for co-op play in some rounds (Survival Waves) while alternatively awarding bonuses for attacking the other player (Gladiator Waves). Two-player games of Nintendo's Mario Bros. could be played as competitively or cooperatively depending on the players' whims. The run-and-gun shooter genre was popular for co-op games. Gauntlet (1985) and Quartet (1986) popularized co-op four-player gaming in the arcades. The games had broader consoles to allow for four sets of controls. Beat 'em up games like Double Dragon in 1987 and Final Fight in 1989 introduced a type of game where both players would work in tandem to clear out all of the enemies and proceed to the next area and ultimately the final boss. In 1998 Time Crisis 2 launched as the first in the series as a two-player arcade rail shooter where two players would go through levels with slight differences allowing each player to cover each other and utilize the environment to create cover. In 2009 Konami and Activision put out Guitar Hero Arcade, a co-op rhythm game which allowed players to work together to complete a song of their choosing or the two players could fight each other in the battle mode with each guitarist striving for a higher score. Console co-op gaming Early-generation home consoles typically did not offer co-op options, due to technical limitations which hindered the increased graphics required for simultaneous co-op play. Though consoles from the second generation of video games onward typically had controller ports for two-player games, most systems did not have the computing or graphical power for simultaneous play, leading most games that billed "2-player gameplay" as a feature to merely be the single player game with alternating players. During this early era, many video games which featured co-op play (including beat 'em ups such as Double Dragon) were ported to less advanced home systems. Alternating play replaced the arcade's co-op play in the NES version (although Double Dragon II and III, for the same system, did retain their co-op gameplay). Most other titles featuring two-player were head-to-head sports titles. Though most of the console beat 'em ups were arcade ports, original franchises such as Streets of Rage and River City Ransom also became popular. In the run-and-gun shooter genre, Contra