No getting air, no combat, no context for the exploration (i.e no story). It's just exploring, finding new creatures of the sea, interacting with the different fish etc. and learning the names of them. That's basically it. There could have been some cool story offered for some of the game. It's too cryptic for me with no answers.
I played it on PS4 which is 30fps. I imagine it's better at 60fps on PC but there's nothing special about the game aside from the art style which is fantastic and the music which really sets the mood and sounds great. Not much of a game to be honest though.