AusGamers has previewed Assassin's Creed IV: Black Flag after getting hands-on with the PS4 version and writes:
"In the dive bell sequences, where you explore sunken vessels and swim freely in the ocean, it's nature's turn to bite back. Not only are you always racing against your own breathless clock, but you need to be wary of sharks, moray eels, sea urchins and more. The amount of times I freaked out after being nipped by a shark or attacked up close and personal by a camouflaged eel was ridiculous. I barely found all the treasure, and escaped back to my ship with only one bar of health and was seconds away from being out of breath. Your crew drop barrels of air pockets into the area for you, but only an agile player will navigate these areas safely, and there's a hope on my part that they become more complex and dangerous the further into the game you get. Suffice to say though, without being able to play inverted, I was practically dead in the water..."