I have a couple thoughts to share but wow holy cow what a unique interpretation of loop--the idea of being stuck in inside Ouroboros is terrifying.
First off, the artwork and mood are very strong. Something about the composition of the environment is really satisfying, I think it's the deep reds of the "ceiling" with the tailbone that fades into the silhouette of the horizon broken by jagged rocks and the murky green water. Between that and the ever-dimming lantern, holy moly this place is scary. Speaking of the lanterns, having all of the most important things (main character and the two npcs) be lit by them made navigation no problem, for better or for worse.
I like the core feedback loop of the game, the more planks you have the easier it is to keep you lantern bright so you can avoid jagged rocks which cost planks to repair and find other planks in the water, but when you're out it feels like you're fumbling through the dark to regain a foothold, and I think that fits with the mood and narrative. I will say though, that as long as I can maintain a decent amount, it feels almost trivial to maintain that, and with no noticeable increase in difficulty between loops as I got better at navigating my boat the less they felt like a lifeline and the more they felt like a chore to maintain as I tried to make my way back to the npcs.
The snake enemies look pretty scary on the horizon when I can only make out the shape of their tails slithering around, but when they're lit up by the lantern they look kinda goofy, which I think in the case of your game breaks immersion a little bit. That said, them snapping and latching onto the boat caught my by surprise the first time and YEESH I jumped. I love the choice to only be able to throw harpoons backwards, despite the fact that you're primarily moving forwards, that makes it really feel like you're defending yourself in a hostile environment you're trying to escape, rather than like going guns blazing.
The UI has a nice layout, and for a game of game jam scale, having the controls present on screen was definitely not a bad idea. If you plan to continue development, though, I'd suggest that you consider paring down the lantern fill bar and just letting the player feel out the brightness of the lantern, as well as reducing the amount of text. I also really loved the character art, both their models and the dialogue portraits. Our player character feels so mysterious, and having a portrait of the granny and a short moment of warmth in conversation in an otherwise hostile environment made me like her, which of course payed off narratively in the following few loops :( I'm not sure why, but I was only able to activate conversation with the hunter one time, which was after restarting the game (because the first time I wasn't able to). If that was a scope issue/bug I totally get it, but based on the fact that I was able to talk to her once, I felt like I was doing something wrong, even though it showed the button prompt to talk to her.
Lastly, I really wish the way the game looped back to the start was smoother. I think more than anything, having my character obviously snap back to the start really broke the immersion of travelling through the inside of Ouroboros. I've not worked with 3d games yet so I have no idea how difficult that'd be, but I think it would've really benefitted the environmental mood of the game, which is, in my opinion, it's greatest strength.
Thank you so much for submitting, I really enjoyed trying out your game!