Nice simple concept with good stakes/hook! The simple controls fits in with the theme nicely too. I reached day 8 before a bug ended my run:
The day wouldn't end even though 20/20 ships came and went. It says I saved 14 and lost 2, so maybe the game lost track of the remaining 4 ships and that's causing the game to think the day is still ongoing? I also didn't see any signs of the ancient creature, but maybe that's intended. If so I'd say maybe show it a bit sooner so the player can be enticed to keep going. Keep up the good work!