There are four mini-games at the Arcade: Dodge Hall, Directional Attack, Web Attack, Air Combo. Enter the Arcade, then go to the back of the room. Press X to activate the marker to start the Dodge Hall mini-game. Complete round 3 to
unlock the Directional Attack mini-game (which is more of a tutorial). In the Directional Attack mini-game, follow it as instructed to unlock the Web Attack mini-game. This is also basically just a tutorial. In the Web Attack mini-game, follow it as instructed to unlock the Air Combo mini-game.