The version shown at The Nintendo Show included the tilt function.
There was a choice to play the game with the D-Pad, or tilt function. Obviously, I chose the latter.
A character was selected for you automatically and there was a choice of five tracks.
The tilt function was easy to get used to, you'll be winning the races after a couple of goes. The console only has to be tipped left, right, up or down. Flipping it all the way will do no good, it responds as digital controls, you will not turn a sharper corner by pushing the console round further in one direction.
I enjoyed the track with the magma level the most. Where the lava rose, it would send you flying upwards if you drove into it. This could be used to your advantage at one point, as there was a speed boost at the top of one set. Other tracks had apple trees to dodge, chickens to avoid and icy lakes to maneuvre along. Beacons stop you from cutting large areas of the track, if you miss going the right direction three times you're out of the race.
Viewing the game from the television screen at the show, I didn't check how the game would play if you were looking at the GBA. However, as said it does not take much to change direction so your view should not be obscured.