Inspired a lot by Nintendo's smash hit Super Mario 64, Sonic Adventure is a massive, breathtaking game that rarely comes along.  Sonic returns alongside his old buds Tails and Knuckles with some other characters to once again battle Dr. Robotnik.  While you can tell this game was designed primarily for younger kids, older gamers will love playing Sonic Adventure.  The levels are massive, the graphics are unbelieveable, and the virtual pet Chao is a cool addition to an allready awesome game.  The only problem is the camera angle can get awkward very quickly on certain levels, causing you to misjudge your distance when you jump and leading to frustrating deaths, but when you get the hang of it, it becomes simple.  All in all, the one Dreamcast game (along with Shenmue which is very recommended) that is essential in your collection if you own a Dreamcast.