6.8 nothing, this game is the best thing on the Wii until Metroid Prime 3. If you see it cheap, buy it!
As far as graphics and sound goes, this game is average. It looks good for a Wii title, but comes nowhere near Burnout Revenge.
Where it shines is the gameplay. While the environment manipulation is simple, it really does help the flow of the game a lot, and the driving mechanics are perfect.
Multiplayer in this game is awesome, if short lived. While it only supports one on one play, the gameplay is so much fun with another person that anyone who picks it up will enjoy it.
All in all, Excite Truck is a very good and very short lived game. Enjoy it while it lasts.