Thank you very much! The water is done with semi-transparent water tiles, and scrolling UVs underneath. The ocean waves are then on top of the tiles.
I totally feel you on the tutorial. I waffled about including one or not very heavily. In the end I decided to try simply making the mechanics as intuitive as possible... but clearly I didn't quite nail that, hah.
(I've had my eye on your game since I saw the screenshots! I'll absolutely be there soon!)