What worked:
The sound design is really good. It feels full and gives it impression of being out to sea. The art and set-up look really great too. I like the feeling of being in a cabin as a viewport. Having to wrestle with the sea works well thematically.
What didn't:
I didn't notice any helpful sound cues. That doesn't mean they weren't there, but I never picked up on any. (I heard singing which is never a good sign when you're alone, but both steering to and away didn't really change much.)
It gets really hard after a certain point. This is fine innately, but I began to feel like there was nothing I could do. I would frequently find myself suddenly in-between two rocks after a long period of darkness, try to steer in the middle, then become faced with a certain other object out of nowhere on the next flash. This is when I can steer at all of course.
I'm still not sure on how close to objects I could safely sail. Was it to the edges of my cabin, or the edges of the screen?
Bugs:
Didn't find any.
Great job! Last time I fall asleep manning a one-man vessel, ptoooey.