" The game´s framerate is one of the game´s biggest stumbling points. It runs at 30 frames per second in single-player mode with occasional slowdown below that. Unfortunately, the framerate gets even worse in multiplayer mode. Even though that sounds like enough for single-player, this is Sonic we´re talking about and compared to the Game Cube and Xbox versions, which run at 60 fps, the PS2 graphics are much harder to look at and follow when Sonic starts to go ballistic and speeds along the course. Since those sections are the best parts of the game, this is a huge drawback to playing Sonic Heroes on the PS2.
Another problem for the PS2 version are the shimmery graphics that give harsh edges to most of the objects in the game due to a lack of anti-aliasing. Where the other console versions feature smooth graphics, expect more headaches from looking at the screen here. Combined with the slower graphics, it´s clear that this is the version to avoid. "
Voilà ce qui va pas sur la version PS2 :D