Sonic Adventure 2 is by far one of Sonics overall best games, improving on two of the gameplay styles from the first game, those being 'Speed Levels' and 'Emerald Hunting'. However the 'Mech Levels' are an overall downgrade from Gamma. This game introduce one of gamings most iconic characters, Shadow The Hedgehog.
SA2 has a silly, yet wonderful story.
Also the Chao Garden is amazing side content. -Logan