Good. This is proof that you can take a formula and do something creative with it. Even though we've seen this style of gameplay before, this feels fresh throughout. Colorful graphics, the little octopus is cute, and the big one looks suitably tough without appearing evil. I really liked the idea that the sliding was produced by the big octopus rocking the ship in order to save his friend.
I liked the little intro too. Watching this little guy cart dragged off by the kept me going through all the levels in hopes of of saving him. I was slightly disappointed not to see an ending cartoon, but there is a triumphant "happy" screen. I didn't play Mirror Mode, so if there's any else there other than medal, I don't know of it yet.
The music is clear and well-played, but I didn't particularly like the track. I did like the sound effects, though. I actually preferred to mute the track so I could listen to the relaxing ocean waves and creaking boards.
The only problem I can think of is that after I beat normal mode, when I reloaded the game I began to have serious problems with the mouse. The cursor has become non-responsive. I have to right-click and pick it up with the arrow if I want to do anything, and it keeps happening. Not sure if that's the game, or if it's a problem on my end.
Other than that, the controls work great and game isn't frustrating. It wasn't quite as challenging as I feared it would be, although the last few levels were tough to three-star. I think you've done a good job.