For most people, doing some stunts wherever they are, would be stupid since they could get an accident. If you got lucky then you would have a few broken bones just by performing some stunts, but those, who are unlucky can't do anything since they are already dead. That is how a stunt goes and those, who performed such stunts are prepared to die. If you don't want that then stop performing stunts.
In this game, you are going to ride a truck, but you are not any passengers that normally rides a truck as you would be situated at the back of the truck full of ice.
The idea in this game is balance. You need to balance your character while you are on the truck. You can only control the movement of your character to the use of your mouse. You would need to press the arrow keys if you want to move, moreover to perform some stunts. This won't be easy as you need to balance your character the whole time. If something goes wrong then your character would be thrown out of the truck.
Do you think you could do this stuff? Bring it on and get ready to balance.