To enable the Level Select option, you have to get 45 License Plates in Story mode.
To unlock Infinite Health, get 50 hidden treasure chests outside of Story mode at the Open Ocean West, Open Ocean South, Open Ocean East, Grand Occasus Canals, Underwater Caves, and Fisherman's Isle. Save the game. You will get unlimited health when the saved game is resumed.
I’m gonna teach you how to perform the Body Bomb. You have to hold L, jump on the water when near the boat. Then release the left analog-stick to make Jaws jump out of the water and sink a boat.
How to launch objects. First, you should try to grab mines and barrels and launch them at your target. Hold Charge and grab an item, then release Charge and launch the item. This method is very effective if you want to destroy objects.
How to sink boats. First, you must have the special ability. After that, you should get someone in the water and hold Black. Then you should swim towards the side of the boat and press R. Choose small boats to achieve the best result.
I’m sure you want to get easy points. Then read how to achieve this goal! Go to the open ocean and go south as far as you can. There, you will meet many boats. If you attack them, you will receive a lot of points. When police boats arrive, stop attacking. Note that you will receive 1,000 pts for sinking a boat and 2,000 for blowing it up.
How to use ability points. First, you have to spend them on Health, then on Speed, Power, Accuracy, and Hunger (in this order). Thus you will get the best attacks and finish the free missions easier.