This looks really well made! But the controls are an absolute game killer for me. If W is always going to be forward, why not make the world be vertical and scroll up? I understand wanting to use tank controls for a boat, but it just felt really bad to control. The combat was really satisfying when I could hit things. And your 'health' being your ship taking on more water instead of gold was a really cool idea.
Overall, you knocked it out of the park on this game. Well done!