There's really not much to say, I've owned this game before but not in Steam. Let's start with a few things people usually ask me about this game, assuming people already know the mechanics of this game.
Is it a good WWII naval warfare game? Not extremely good, it's enjoyable. There is a distinct difference between the two campaign and each campaign can take a pretty lengthy time to finish. Nothing feels that much repetitive except maybe shooting down a seemingly infinite amount of incoming planes in certain missions.
Is it realistic? No, back then when it was first released it was marketed as an 'authentic' experience, doesn't mean it's realistic but you do get the feeling that you are in control of a giant battleship, an intimidating bomber, a sleek fighter, and all the other units in the game. It's personally just a pet peeve of mine but real naval battles of world war 2 would take hours to days to finish, with ships exchanging shells from tens of kilometers away. In this game, 3 kilometers is apparently too far for a 460 mm cannon
Does it age well? No and yes, the lack of support for this game makes it impossible to do online multiplayer, however you can expand your singleplayer experience with various mods. It's a shame because the multiplayer component was a damn great fun. And yes, the game can still look pretty beautiful at certain lighting angles, not much to say because at least 90% of the landscape is water, nothing particularly special.
Is it 'fun'? Depends, some missions can be pretty harsh at times and require fast reflexes to effectively give commands and switch between your available units in higher difficulties. They are not incredibly frustating and you never feel cheated by the AI. But those lucky AI shots that crippled my engine, blew up my ammo storage, and set my deck on fire? They are pretty annoying, yeah, but all is fair, because my torpedo bomber blew up a hole in their hull big enough for water to flood in and make the ship list so bad that she can't use her cannons.
Should you buy it? Yes and no, if you are desperate for some naval warfare action where you are in control of the units instead of just a strategy game where you watch ships blow each other up, sure. Otherwise no, unless it's on sale