Zombie Revenge Classic
The Matrix has 8 beat 'em ups on file for the Sega Dreamcast, released between 1999–2000. 3 of them support multiplayer, including 1 with co-op. They're ranked below by legacy score, so the games that shaped the genre on the Dreamcast come first, with lesser-known picks further down.
Beat 'em ups send you down scrolling streets fighting waves of thugs with punches, kicks, throws and grabbed weapons. Most can be finished in a single sitting and shine with a second player.
Typical commitment: quick session (under an hour, or endless arcade fun). Tip: Avoid getting surrounded: keep enemies on one side of you and save your special attacks for crowds. Bring a friend if the game supports co-op.