This game is reeking with soul! I had a lot of fun with this one. I had a couple of issues though.
- Firing cannons, while being fun feels luck based since it's impossible to know if you are going to overshoot or undershoot. With a third person view of the ship this would be easier to judge based on the waves, but from a top perspective this is impossible, even when zoomed in. My suggestion is to add maybe a third person camera or some kind of projectile indication, like you hold down the fire button and you get an rough indication where the cannon balls will land.
- Getting hit and hitting enemies should have more effects, like smoke and sounds of wood getting torn apart. I was often left wondering if I hit the enemy or not.
- The mines sometime stops homing in on enemies and seems to be disabled.
Keep working and add polish on this and you'll have great game in no time, the foundation is there.