It took me a while to get to grips with the game, on my first run I was all planks and no cannons and I didn't understand the shops, I totally missed the "sell" button on the side so I never had any money. Healing 300 hp per turn but having to wait 6 turns to get both my tiny cannons available was pretty tedious but I started to get the hang of it when I found the sell button. I liked the strategic element of trying not to kill things to give you more time to upgrade your cards. I did find that I ended up with so much offence, that was really hard.
It would be nice to have more differentiation between the ships to get a better idea of their power level.
I wasn't able to defeat the kraken but having seen your comments about gems being able to upgrade the cards above 100, I might have another go because it was a fun game. Still no idea what you're supposed to do with the Rhum though.
One thing I noticed, and I don't know if this is a bug or intentional but sometimes I would accidentally play my reserved card before drawing a hand and that gave the enemy a free shot at me. (also sometimes, after playing 4 cards and reserving one, the game didn't proceed and I had to play the reserved card too).
It would be nice to see what cards the enemy is playing - or if they're just static stats, have them displayed all the time to make it easier to see what's going on