The brains you collect during gameplay will be added to the grid at the end of the game and when you fill it you will be rewarded with a scratch card. Prizes range from new backgrounds to bonus items. Collecting brains is worth doing if you are trying to save money to spend at the store.
Timing
It is crucial that you time your first jump correctly otherwise your game could come to an abrupt end if there are large groups of moving vehicles. Make sure you always listen for the early warning horns and have your tap finger poised.