Sonic 1&2 are the good old faithfuls from ages ago. I like both of them. They are just like they were.
I am really enjoying Sonic 4 too. It is a lot more faithful to the earlier games than other recent Sonic releases. As far as Gameplay goes I think they are all worth a purchase. IMO Sonic 4 looks the best.
Game Centre, Openfeint, Crystal, Gameloft Live and PSN ID: Smallville2106