If you're a half way competent gamer I wouldn't advise spending too much on this game. It's extremely repetetive, most missions are far too easy and I found that I completed the game in no time at all. It's ok for a while but don't expect realism, you'll find yourself single handedly taking on a dozen enemy fighters and more often than not you'll shoot every one of them down within a couple of minutes. With most missions there isn't enough of a challenge and as a consequence you'll soon get bored.
One other strange aspect is that the bad guys are always referred to simply as 'the enemy'. It's called 'Battle over the Pacific' so I think we can guess who are meant to be so why be so coy?