As you are running, you will see a whole bunch of bananas that do not pose a threat to your life. The goal is to collect as many of these bananas as possible. Snag one of the rare rainbow bananas and you will score big. These bananas are used as an in-app currency to purchase power ups in the jungle shop. Banana Kong
Some power ups will stay with you throughout the game like the Magnet, which will attract the bananas towards you as you run (the good bananas of course). Other power up utilities will only last once on your next run, like the water bounce ability. This will allow you to skip across the water rather than sink; a good ability to have if you the find the water hazards in the game are too difficult to avoid.