As you play through each character, more facets of the plot are revealed to you. At one point, Sonic and Knuckles fight. This type of thing happens at least five or six times throughout the game, and after awhile, it just gets really lame and tiresome. Better plot writing could have avoided this easily, and made the game MUCH more interesting to play through. Bottom line is, Sonic adventure is a mixed bag.
Some parts are a dream to play through, while others are sheer agony.
Now THAT would have been cool.