Story
None of the games have much story. But you get enough to know why these machines deserve such gruesome deaths. But aside that sonic 2 has the greatest ending of any game ever, why? Oh just because...
Graphics
Excellent for their time, with great detail and (even today) an excelling frame rate. Sonic 3D embarrases even PSone games!!!
Music / Sound
Each tune is unchanged, and still some of the best music ever, the sounds are also perfect.
GamePlay
It's not about the high score. It's not about saving anyone, it's how fast you are! Can you beat green hill act 1 in 1:00? Course that is slow. But in Sonic 3D it is a seek and rescue game. And kill, never forget to kill. Mmm... kill.