There are a ton of missions and objectives that you can accept or ignore or go back to later and at the same time can just swim around if you want to. It's for the most time up to you. There is a main story line to go thru, but it's at your own pace and when you finish the story which doesn't take long there is a ton of stuff still left, seperate missions, treasure hunts, guided tours, training dolphins, manage a 1,000,000 gallon aquarium, find legendary creatures such as the Kracken, fending off Tigers and Great Whites, etc. I can't list them all. Too bad I'm not getting paid to advertise. I think it's time to play again.