Improves on the original in almost every way.
Those of you who played the first will have no trouble at all in learning few things that are new. It still handles the control of your ships and planes very well, with improved interface and options. On a wider note, the physics have incredibly improved so when a torpedo hits the right spot on a freighter, a huge opening will pop and take on water. You now have the ability to change from 3rd person view of a plane and to 1st person with a view from the cockpit and believe me, the cockpit view feels stunning at times due to flying feeling and amazing visuals. Jet kamikazes have been introduced as well and fly incredible fast. People on land are not merely for display because with the new ability to send landing craft to capture an island, you can watch the soldiers on both sides shoot at each other, or you can fly in and blast away at enemy troopers who are hurting your invading men. Some new features along with new planes, ships is everything you would expect from a sequel.
It is not just the gameplay that has improved, but also the single-player. Not only is there a skirmish introduced with modes like 'Island Capture', 'Duel' etc, but there is a full Japanese campaign. The US campaign is great, but Japanese one is the highlight. It follows alternative history as to 'what if' the Japanese won at Pearl Harbor and in the entire Pacific, and fortunately offers a humane portrayal of the Culture rather than the usual demonizing image in many WW2 movies/games. Both campaigns feature their own lengthy, artistic cutscene along with another one at the end of the campaigns. The main pity is that Japanese don't speak their language like in the bonus missions of the predecessor, but if the proper accent is there then I am happy enough although I still would have preferred the language with subtitles.
Visuals are not the best of the year, but significantly improve from the previous game. The water is quite possibly the best I have ever encountered in gaming visuals. When you are in a submarine, you can now see underwater corals which creates more believability in the world. Subs now levitate more properly and when they reach the surface, splashes of water slide of the skin of it. Of course, the islands are quite detailed in landscape as well as the ships. The frame rate and unbelievably short load times do have a habit of making few changes to the experience on their own, unlike the usual unstable experience that you find in some games.
The sound effects are also quite well executed. Biggest downside to sound is voice-acting. It sounds so childish and flat and undignified at times. You don't really feel the triumph a sea captain would really feel when he confirms an enemy ship sinking. Same goes for when a pilot claims that he is 'going down'. I cannot say which campaign features better because some voice-acting in the Japanese campaign is better while other voice-actors in the campaign do it even worse than American campaign. That's the rubbish of this game, but it usually is not a massive bother for me. The music is composed by Richard Jacques, one of the geniuses behind 'Mass Effect' and the composer of Battlestations Midway. Some music from the previous game is in recycled with improvement while there are some new themes like the Japanese submarine battle theme (my personal favourite as it is for few other people I know). Each is well done and manages to give a sense of epicness to the battles.
There are still a couple of flaws with this sequel, but it improves in more ways than you would expect from some sequels and it is better than the original. It definitely deserves its stand as one of the most ambitious and complex WW2 games this Century. The original may be a good game to start with to get used to controls, but if you do not like it, then you will surely think this sequel is better.