You are an experienced diver on an outing to learn more about the marine environment- but it's so much more than that.
And now, on to what's important: the gameplay. You use a small cursor from the Wiimote to change your direction, and B to swim. While it is somewhat awkward at first, it actually works out better than if there were analog control. You move around in a similar manner on your boat, which serves mainly as a hub to travel across the sea, as you have a limited diving range. You learn more about fish (but only one piece of information out of three about each fish type per dive) by focusing on them with A, then interacting with them by feeding them, petting them, poking them (of all things) and even using your water-proof pen to get the attention of the creatures in the abyss. You can even ride on the back of some sea creatures (specifically whales and dolphins) by focusing on them and grabbing their backs with A and B.
On the subject of dolphins, you can also train dolphins of all sorts to do tricks, and even take them with you on your diving trips. A dolphin will "request" to become your partner after you gain two pieces of info about it, and you can have up to three partners at a time. Teaching them tricks is really just a fun little minigame, but when you take one with you on a dive they can point you in the direction of treasures they may find, and you can ride on their back.
There are many kinds of Dolphins you can befriend, including some that shouldn't be in the tropical waters of the Manauri Sea. This is where the game's true controversy comes in- its lack of realism. You find creatures you shouldn't, including Polar Bears on your boat and Belugas in an ancient city. Though you can only dive for about an hour or so, there's no realistic oxygen limit. And the big clincher? You are never in any sort of danger. You can find the most violent creature underwater, a supposed sea god who took the form of a shark, and yet you can pet it without even fearing being knocked back a bit, although it does have a thrashing animation. However, in my opinion this is the true beauty of the game- the freedom.
Now tell me. When you play a videogame, do you want an experience that constantly reminds you of the real barriers of life, or do you want a game that lets you be free, and do what you want without worrying about real life's limitations?
The game is graphically beautiful- you may not be able to see individual hair, or wrinkles on your scuba suit, but the work they put into the graphics on this game is amazing. Everything is stunning, and truly adds to that "oh my god, I'm scuba diving" feel.
Endless Ocean takes an interesting take on the musical score- most of the game's music is by an artist named Haley Western, and while her music isn't actually good for just listening to on its own, It really goes well with the setting of the game. It's a perfect fit. But you know what? Let's say you absolutely hate every song in this game for some reason. Do you have to turn your volume off? No. You can actually bring over your own music on an SD card, and listen to that while you dive.
Plot: Endless Ocean's plot isn't exactly great, but it isn't very over-bearing on the actual gameplay, so most of the time you forget there's a plot at all. As such, I give it a measly 6.5/10
Gameplay: While the lack of realism may be either appealing or appalling, if you can look past it, this game is a truly engrossing but relaxing experience, just as a diving game should be. 8.5/10
Graphics: The graphics are incredibly beautiful, and while they could be a little more detailed, they still do a good job and fulfill their purpose. 8/10
Music: There's really no justification for giving this less than a 10 when you can use your own freaking music. 10/10
Re-playability: While I didn't really touch on the game's re-playability, it's still decent, as there are many animals to learn about, areas to explore, treasures to find, and character customization options to unlock. 8/10
Final Score: 9.2/10 (Not based on an average)
Endless Ocean is a truly relaxing and full game, but the lack of danger means that it's not for everyone.