Description taken from PlayStation 2 version of this game

Sixteen stars from Sega's best-selling franchises are brought together in this lighthearted tennis game from developer Sumo Digital. Included are characters from such titles as Jet Set Radio, Space Channel 5, Samba de Amigo, Nights Into Dreams, Super Monkey Ball, and Sonic the Hedgehog. Each character can compete in four tournaments held on ten themed courts, from Sonic's Green Hill Zone to Out Run's Coconut Beach. Winning matches will unlock an assortment of tennis-oriented mini-games, each with a Sega slant.

One mini-game, for example, involves batting down zombies from The House of the Dead as they stagger and shuffle across the court. Another involves graffiti tagging a court's surface by hitting cans of spray paint. Exhibition matches allow players to pick and choose characters and courts for singles or doubles play, with the latter supporting four-player simultaneous action. While serving up aces and returning volleys, players can listen to multiple tracks of signature Sega tunes recorded in Dolby Digital 5.1 surround sound. ~ Scott Alan Marriott, All Game Guide