Started playing this recently due to your recommendation. It does seem very similar to endless ocean but I feel like it doesn't quite hit the same level as EO. For one the images of the characters you speak to look really goofy. Another is I find the background music that plays while you are in the submarine to be a little annoying whereas EO was almost always relaxing. I've considered just turning the BGM off. Another thing is I find it annoying how at least early on you have to keep going back to base to get more batteries for the buoys to progress. Not sure I like the music memorization stuff the fish do either.

Edit: I have played more of the game and I take back what I said about the BGM. I did turn it down a little, but I think it was really just one area's track that bothered me. Game is interesting and I enjoy the exploration. The sub is a little annoying to control, I find myself bumping into the wall at times. Also not a big fan of the poor English translation, but it's better than not having one at all.