The lack of depth and truck feel to the game lets it down.
The game as it is involves you picking a truck, racing with it and trying to rack up your stars and hopefully come first in the race. You work your way through each of the cups in hope to become an ultimate truck racer - however, there is no storyline (not that a game like this particularly needs it).
The aim of the races aren't really to come first - that's more of an added bonus. You really just want to get stars by doing crazy jumps, smashing up other trucks, jumping through hoops and speeding wildly through masses of trees in hope that you don't get hit and earn a star for a 'great smash'.
There is also a short challenge mode with merely has six challenges in total, three different types. The first type involves you smashing other trucks in a certain time limit, which is great fun and really tense as you speed towards an enemy at full pelt, hoping you'll hit it bang on target and see it flying. Other challenges see you racing through gates or jumping through hoops.
One factor that lets the game down is the trucks. There are around ten or so different trucks in total for you to pick from each with different abilities (some trucks may have better handling, for instance). However when you are actually driving the trucks or grabbing massive air, you really don't feel much of a difference between the current truck or the one before it.
Another let down is the depth to the game. Although the current concept is good and a top Wii game, it could have been a whole lot more if the developer extended the ideas further and added more depth the game.