Extremely fun naval warfare, fairly well done campaigns that lets you play as both Allied forces and IJN, as well as a good variety of Skirmish maps and modes.
Island capture mode can keep you busy and having fun for hours, with a huge variety of units and tactics available- you can build up a sizeabe fleet and wrest control of Islands by way of LST's and Cargo ships, or parachuting units in by air. The naval battles themselves are intense with visual damage and listing to ships that have suffered heavy barrages, and some of that damage remains even after repairing which adds a nice touch of immersion.
Whereas Duel, Escort and Siege modes are more to the point fixed objective modes that have a nice degree of variety to them, including outright 4v4 Battleship duels, destroying an anchored fleet in a Ohka suicide rocket, various naval and air escort missions,
The overall amount of freedom you get in Island Capture mode allows you to sort of make your own scenarios as well, such as spawning a ton of Cargo and LST ships and a small destroyer escort and try to make it all the way across to the other side of the map against a Veteran AI - guaranteed fun.
If you like the naval warfare in Battlefield 1942 - especially on Midway Island, then its a sure bet you will like this game, only the naval battles and air battles are much larger in scope and scale. There really is no other game in the world like Pacific or Midway, just like there is no other game in the world like Battlefield 1942 with its true actual naval air and land warfare, so its a unique game in that respect.
Furthermore there is a dedicated and passionate modding community, that despite zero officially released mod tools or support, has managed to create a few dozen mods of all types, extra command points, retextures, realism mods, overhauls, etc. And they are still working on newer versions, it has one of the most dedicated yet small modding communities you will ever encounter.
Now onto the really ♥♥♥♥ty part - the developers are no more and all of the three DLC's they made were only available on Games for Windows Live, which is also dead now. On one hand we can rejoice that GFWL is dead, yet on the other, the geniuses at Eidos/Squeenix decided to only give GFWL PC Marketplace the DLC's (two map packs and one unit pack with 3 units- including the Montana Class Battleship). So now that GFWL is dead and the developers have also been axed, there is no way to purchase or otherwise obtain these additional maps and units, which is a serious error on Squeenix's part.
I don't know why the DLC's aren't available on Steam yet even though the game is, I would at this point happily pay to buy all three of them even though the developers and the IP are now gone because the Battlestations franchise does not deserve the fate its been given, its incredibly frustrating to want and purchase content for a game that should have been there anyways and yet to find now that its no longer available. It would be really nice if Steam somehow acquired those DLC's and brought them back for sale.