I hate being in the ocean. Shallow beaches, I can handle, but the deep sea terrifies me more than spiders, snakes and birds who can talk put together. So a game where you do nothing but drown in open water is not my Game Of The Year candidate.
But Sortie En Mer isn't supposed to be fun. It's supposed to be effective.
You "play" a French dude who falls off a boat. And no matter how good a swimmer he is/you are, or how fast you think you are, eventually you will run out of energy, you will drown, and you will die. It's a dark, harrowing experience.
While at the end of the day this is an ad for "yachtwear" company Guy Cotten, it's a better advertisement for always wear a lifejacket.