This game has some cool concepts, but when it comes to the upgrades to proceed, it centers around the boost too much, basically as long as you have enough boost your fine, but there should be other variables that you should be able to upgrade, like Armor, Suspension and Gravity (Lessoning the Gravity in order to get more air), but aside from that, after you hit a ramp and use all your boost, and land on another hard surface, your car flips and you can no longer continue to drive, if you land on your wheels it should allow you to continue to move unless it is too damaged to do so (which is where upgrading the Armor and Suspension would come in)