Planet 51

You can actually get hit slightly in these tasks and still obtain the achievement. It is when you physically see a piece of your vehicle damaged or when the AI hits you and you spin in a circle for a brief moment. If either happens you will have to retry. Also to be on the safe side DO NOT drive over the “Repairers” which are the “Blue Circle” that repair your vehicle, because they may cause the achievement not to register. This is best done in the “Suburbs” Car Crusher tasks. Opposed to the later game sections, where the AI is more vigilant. Once defeating the designated amount of enemies in the task with out taking damage the achievement will unlock.