Clearly the game is beautiful. The best-looking game I've played on the jam so far. And I also want to recognize how well thought out and put together your menu is, and the introductory writing and tutorial.
But then I will echo a few points made by other commenters. I'd definitely appreciate more UI for health and progress and possibly enemy health. Your moon eclipsing gauge was so brilliant I would have loved to see that applied elsewhere.
And lastly for gameplay, I thought it was the only real weak point. I died on the boat and really wanted to get to the parts in your screenshots, but didn't have much incentive to keep playing. I didn't know how much longer I had left on the boat, and I was craving to do new things in the game except deal with more and more bad guys. And maybe the later levels do offer some innovative gameplay, but then I'd recommend nerfing the boat level, or adding some metagame (maybe some items to collect or a reason to dash around the boat) in the middle of it so that players don't lose momentum and give up.