One of the best Sonic games, I can see why it is loved a lot. Great music, good level designed, story good enough, the final level after beating both story will need many tries and be frustrating but the final boss is kino as hell with the music and all. Recommand a lot, do not need to play Sonic Adventure DX but if you wanna do it, please do DX first and THEN go for Adventure 2, there's a large difference of level design between those 2 games.
PS : Fuck Knuckles/Rouge levels :,)