Nice gameplay loop with the hunting, selling, upgrading. Could probably be extended with more content to make it a bit more long-lived, but quite good for a game jam entry. The voice acting was a nice touch.
Maybe something to add would be an incentive to explore more. I see that others found interesting places that I didn't think existed. You can get by with just hunting around the shore right in front of the shop.
Took me a bit of time to get used to the harpooning mechanic, but after that it was pretty nice. The vendor UI was a bit rough and it took me a long time to find the "Resume" button the first time. I think there was also a bug when I tried to buy the last harpoon update where it stopped updating the UI (said I couldn't afford an update when I still had over 1000 coins).