Wow, my friend showed me, a while ago, a picture of someone requesting a game similar to this. This looks amazing. Downloading it right now. I don't have time to play until some time this evening, though. I'll let you hear back from me after that!
EDIT:Meh, I couldn't resist. I tried it.
I'm sorry to say, however, that I'm a bit disappointed. :/
The initial premise was great. A clear view and a pretty ocean. A fearsome beast appeared and I fired my cannon (which I felt very bad about doing, though; you need to give me some storywise motivation to attack this poor beauty!

).
However, the screen was soon covered in this
constant vignette of obscured edges, which really made no sense as the rest of the sky was as bright as before, and I felt like I was wearing some sort of goggles with my side vision covered. Even worse, though, I kept getting eaten by this creature that was nowhere to be seen, no matter how much I turned the boat and my head. Again and again. I finally got one more glimpse, but then that was it.
As for technical problems, the control scheme screen
had parts missing (also, how come the mouse was shown [also partially obscured] when I accessed the controls from within the game, but not on the loading screen?), and when I had lost, the button to go back to the menu didn't work, and eventually it faded to take me to a new screen, so why were the buttons there at all?

Nonetheless, I love the premise and I love the visuals (when I'm not forced to wear goggles). The steering was a bit weird. I felt like the character was almost lying on his stomach on the deck rather than standing up, the way the camera was placed. As for aiming, you might want to get some inspiration from Wind Waker, though it seemed you might actually have done so. Study it some more!
I love the icon. Fantastic. Very, very pretty, with the whale and all.
I'm not sure, because I forgot to read it properly, but I believe the monologues had some spelling errors.
What's that code-lock looking counter thing in the top for? What's the day counting system for?
Pressing 1 for the journal doesn't work, but I guess you haven't added that yet.
To summarise, great idea, great visuals, great audio. Controllers not so great, visuals not so great in different aspects from those in which they are great; namely, the graphics are pretty, but confusing and not so helpful.
Keep working! I'm sure this can turn into something great.
Give me a proper incentive to kill off those poor animals, though! Playing Shadow of the Colossus, I only killed the creatures because the mechanics were fun, but there was no mental motivation to do so. To save his girlfriend? Who is he? Who is his girlfriend? Why should I care? Why should I put a girlfriend I don't know above these magnificent beings and kill them for her sake? I don't want to do that!

See what I mean?

Keep going!
Oh, and one really nice thing is that despite the game being made in Unity (misextracted the .rar at first and found a lot of Unity files), it doesn't look like it was, which a lot of less polished games in Unity do. That's very good. You might want to figure out how you can make the menus a little less blurry, because you don't want to scare people off from your pretty game by having menus that are not on par!