I caught several fish. I gave the first to Lua, and got some item that she said would improve getting stuff for her. I gave the next to the king in the area below, who rejected it and said to fish in the rift for him. I went back to the starting area and tried to go right, but was pushed back. There was something that partly showed at the top left for a short time when this happened, but was not clear. I could not go through the left from the starting area. I fished some more and caught a shark. I gave that to Lua and suddenly she fell in love and the game ended. That felt very abrupt. A jam demo being short is fine, but the story of humans hunted my kind, but one gave me 2 fish and now I'm in love, just didn't work for me.
I restarted while writing this. I did no fishing, and when I tried to go down to the king's area I was pushed back, same as in my previous game when I tried to go to the right, only the thing at the top left was different, and was the item I had gotten from Lua in the first playthrough. Now I understand that it is showing the item needed to unlock the next area. My guess is that I needed to give the king something better, such as the shark, to get his item to unlock the next area. That was not clear from playing and could use with something to tell the player what it means.
While experimenting I clicked on the book at the top right. It could use a bit more of a hover effect to indicate that it is interactable with the mouse. If there are any other clickable things, I did not notice. I tried a few spots, but with clicking also starting the fishing mini-game it was too annoying to do it a lot. I'd also add a mention of the book being clickable to the game page notes on controls. The first time I opened it I missed the tabs for turning pages. I was just starting out and had not moved yet, and I think the look of them just blended into the background to much that I did not see them as tabs, but something that was part of the land behind. I think they could use a bit of tweaking to look a bit more like the book, and less like the land. It would also be nice if you added hover tooltips to the book with details, such as names of things, and maybe other stats or flavor text.
In general, the game could use with a bit of improving of the UI, and intro to the game. It seems like a good start, but I felt a bit lost on what to do and what was interactable, then, before I felt like I understood the game, it was over.