This game surprised me a lot! I liked it so much that the very loose connection to the theme didn't really matter to me. The atmosphere in the game immediately puts you in the mood to explore and take in the sights.
It would be even better if the world was more dynamic like having a day/night cycle with pretty stars or a rower that plays cute little idle animations or even having the items you collect bounce around like physics objects.
Another critique is that the speed of the boat needs tweaking, it feels too slow at the start and too fast at the end, it made it hard for me to grab the last few items. Alternatively, you could make the colliders on the items bigger so they can be grabbed easier.