The critical hit needs to be less powerful. A sloop got a critical hit on my galleon, which had full health, and it was killed. It would be better if it, at best, did 4x the amount of damage as normal, instead of just killing them instantly.
Final mission: "The buccaneers have an extremely powerful thing. I can't overstate how strong it is.", Says the commander. "This will be your hardest mission yet." says the other guy. I get there and OMG IT'S A GHOST SHIP! It has thirty health and I kill it in one hit. The most anticlimactic and hilarious thing I have ever seen!