Sonic Adventure 2 Battle
Sonic adventure 2 battle is just kinda a huge upgrade to Sonic adventure 2.  It's just about no upgrade in the graphic and single player wise.  Multiplayer wise its like 50 times better.  You can play with 6 more characters than you can play with in the original sonic adventures 2 multiplayer mode.  There are around 50 more multiplayer levels but I'm not sure I don't have the new game yet.  I played it at a store which shall remain unmentioned out of fear that they have copyrighted their name.  One of the new levels is  pretty much just about grinding and keeping balance and speed on the rail longer than your opponent can.  One of my favorite things is that they added a new choagame,  choa fighting.  Also, in the baby choa garden inbetween the rock and sky, there is a glitch,  this glitch lets you walk out onto the sky and see the island behind you.