I love the graphics, having using pico-8 myself I know how difficult it can be to get across a coherent and nice-looking aesthetic, but I personally think you nailed it here.
The gameplay is pretty simple to be able to pick up and play right away which is nice, and it did manage to keep me engaged for a fair bit of time.
One thing I would add are borders at the top and bottom of the screen so you can't 'fly' the boat into the sky.
Overall, this was a solid little entry, and one that I should try on a pocket c.h.i.p. sometime, that seems like it would be a good fit. Nice work :)