Endless Ocean starts you off in the shallow reefs of Manoa Lai. You have very few tools at your disposal, you can't swim at night, and the creatures that inhabit these shallow reefs are far from awe inspiring. At this point I immediately regretted my purchase, but I pushed on in hope of better things to come. Smile gentle reader, for I was not disappointed.
Through the 20+ hours of oxygen I've used in the game I've seen every underwater landmass you could imagine, numerous species of whales, sharks, dolphins, and penguins. That is without the cooler locations that I don't want to spoil. The in game catalog of creatures is 40 pages, it has 1 to 4 animals per page and I have found about 60% of the animals so far. While you can easily visit all the locations quickly, finding all the animals and treasures will take some time. If you search FAQs and walkthroughs for the game you will find that there is still a lot of information people don't know.

The game is divided into two components. Your boat is where you take care of reading email, saving your game, organizing your photographs, playing music, viewing your treasures, piloting your boat, and seeing which species you have discovered. In addition you can befriend up to three pets (mostly dolphins) which can be trained to do tricks from the boat. In addition you can fast forward time if you wish to dive specifically at night or during the day. The boat has been described by many as oddly designed and not up to par with the meat of the game which takes place in the ocean. To me the boat is more or less a glorified menu before embarking into the sea where the real game is played.
Many people describe endless ocean as not being a game, and I don't know how I feel about that. While there isn't heart pumping action there is still a storyline and set goals to accomplish. Tasks include scouring the ocean floor for treasures, finding certain species to photograph for the local magazines, taking people on tours of certain areas, and advancing the storyline. The plot is not forced on you and you can really take it as slow or as fast as you want. Aside from simple exploration though there isn't much more to the game.
Luckily the graphics underwater are amazing and finding species you've never seen doesn't get old. The musical score that comes with the game does an amazing job sucking you into the experience as well. Exploring the oceans is enjoyable and seeing the beautiful world of Endless Ocean is a reward by itself. The ability to play your own mp3s through your SD card is a very welcome feature too. Your own music adds extra frosting to an already delicious cake.
Endless Ocean also supports wifi which allows you to explore the ocean with a friend. After entering a friend code its very simple to join someone else on their boat and then proceed to go exploring. Like most nintendo games the experience is made very awkward due to lack of communication. There are a limited amount of preset phrases but they are not adequate. My advise would be to chat on AIM or the phone if you choose to take advantage of this feature.

My complaints about the game are very few. When you pilot your boat to a certain area, you are limited to exploring within a radius from your boat. I'm not sure why the game was designed this way. It can be annoying when you are swimming and suddenly are told you need to turn back. You get used to it though. My other complaint lies with reading music from the SD card. The file must be selected from the boat and it continues playing when you dive, once it ends though you can't select a different song. Nor can you choose music from your SD card in the middle of a dive. It has to be done from your boat.
Final Thoughts
My final advice is pretty simple, Endless Ocean is a game that defines the wii and shows hardcore gamers that good casual titles can exist. While there is much to enjoy about the game, it isn't for everyone. If you've read this entire review and find yourself interested in the game, I can say with some confidence that this game is for you. Check out some videos on youtube if you're still unsure. They'll either finish selling the game or show you that you were right in passing this one up.
The $30 price tag is a huge plus, the game is worth every one of those dollars plus a few. I don't think I would have bought it for $50. I don't think it would have been worth $50, $40 maybe.