My two cents and a few tips upon completion

[SV_Mallet]

This game had surely caught me by surprise. At first it seemed like a good mobile game, but then I caught up with the raids and enjoyed it thoroughly, against all odds.

Difficulty: Once you figure out the mechanics, the game becomes challenging on the Heroic Difficulties.

Strategy and mechanics:
Guns, guns, guns! The game-play consists of two stages. Ships shoot-out and the tactical battle. Tactical hugely depends on how well you'll manage ships battle. Here are the best guns in the game and why:

Best cannons - Glass, CannonBreaker, Shipwrecker. Basically these three are the most important of them all, till the end. Break cannons first at their turn. Break HP modules, Rum(healing) modules and armor modules. Consider leaving the modules which reduce HP, but give damage standing. It'll make tactical much easier.

Decent cannons - Heavy, Light (on higher levels), Crew killer(situational on higher levels)

Worst of the bunch - Mortar(works at stage 3 and pretty useless), the rest.

As for upgrades, do a lot of raids at the beginning to accumulate Blueprints and glass. Invest first and utmost into upgrading the command points and increasing the amount of permitted cannons. At the same time invest into the amount of specialists (Though you will rarely need more than 4).

Crew. As many had mentioned, the best member is my far the spear lady, combined with her Heavy arm skill. The worst one is Musketeer. The rest are ok, but I also preferred a grappler combined with cutthroat as my fourth.

It's better to level up a bit before advancing through the story.

Despite very enjoyable 30 hrs, this game feels like a missed opportunity. Pretty fast you run out of upgrades to do and all that remains is to do the same thing over and over. It could have been so much more.

In any case I would recommend the game never the less. A pleasant surprise.

[Great White Shark]

"Nevertheless," one word.

[Trolleur_Durden]

For me Backstabber > everyone else, because there's a starting module giving them +1 damage. Combined with some secondary classes giving both damage and extra attacks like Cutthroat, their damage is outstanding.