Nicely done, especially the little minimap. I think it would've been cool if the ship had some physics (e.g. didn't stop on a dime when accelerate is no longer pressed etc), and maybe an island counter so you know how many are left? As others have noted, the lighting also seemed a little stark - and perhaps some more details could've been added to make the sea a little more lively.
But that aside, it was a very chill little exploration game!