This game blew me away back when it came out.  It's still impressive.  The levels were by far the biggest I'd ever seen in a racer (although I'm sure there were bigger at the time), and it was just incredibly fun, filled with short-cuts, beautifully placed speed-boosts, destructable environs, etc.  I can't believe there's no sequel to this--I thought it was really popular.  Incredibly fun game.