As listed on the Amazon page, this game is available for a really low price...it's definitely worth it.
You always hear with these strategy games that it's 'infinitely replayable.' I don't suppose that's true about most of them, and it's certainly not true about this one, but you can get a lot of different games out of this one scenario, and if you have an interest in wargaming, or WW2, or both, then you're likely to enjoy HOI because you can play the scenario from so many different perspectives. Want to play historically as Germany, the USA, or the Soviet Union? Go for it. Want to drive the USA into the Communist brotherhood, play as a pacifist USSR, or be a Japan who DOWs on the USA in 1936? You can do that, too, more or less.
It does all get a little old after a while, maybe because despite the plethora of different routes the game can take some things always happen - there's always a great war, for instance, Germany, the Allies, and the Soviet Union never completely abstain from conflict. It would be pretty dull if they did, I suppose, but I just mean to report that some things always occur, or almost always do, and it can make things a little repetitive.
I'm no hardcore wargamer, but I have heard complaints about the combat format, as well. I don't think it's realistic, not close, but it's absurd either. Sure some of the rules about engagement (like, no more than 24 defenders whereas you can attack with 100+) and the reliance on a province-based movement scheme could've been designed better. And the game is arguably too easy, the only way the AI can match an experience player is through all sorts of cheats (of course, there are few strategy games about which that could not be said). And there's limited multiplayer capacity, at best.
But these are minor complaints. The game is certainly enjoyable, and you'll get waaaaay too many hours of zoned out fun immersed in it.