Unfortunately for you, the entire game has changed drastically.
Faust is the least changed, and he has 3 new FRC points, new tragectories, 4 new items, and 3 new moves.
Venom has a slower playstyle, but doesn't have to worry about too much, since he still plays essentially the same. Oh, and 5 balls now instead of 4.
Potemkin does less damage and has more stun, and the Buster is slower, and it's not possible to HS combo into it.
Overall, the game is better though. Force breaks are awesome. Definately worth the 30 bucks I spent.