The First 15 Minutes of Jet Grind Radio (Dreamcast)

Copied from MobyGames:

Tokyo-to, a city not unlike Tokyo, somewhere in Asia, in the near future. This is the story about the GG's, one of three rival teenage gangs who ride motorised inline skates and are tagging the streets with graffiti. There is a turf war going on between the gangs GG's, the Poison Jam, and the high-tech freaks, the Noise Tanks. The evil Rokkaku Corporation has the corrupt police in their grasp, and, headed by Captain Onishima, the cops are hell-bent on subduing the unruly teen protagonists. But there is light in the darkness: the underground DJ, "Professor K," and his Jet Set Radio station keep tabs on what is happening on the streets of Tokyo-to, and soon our teens will have something much darker than the police to worry about.