Crappy graphics aaren't that bad once you get used to them...but forget all that...this is a super fun game if you are into war games. It's easy to play and a lot of fun. That's what it's all about right?
You can dive right in, but reading the manual won't hurt. The cool thing is that your strategies will work! That is, the game is fairly realistic and has a good feel to it. It's also not hard. You have a fair chance.
I bought the boxed version some time ago and it was a lot of fun. As others here have said, once you get into it, you're likely to play for more hours than you planned. And due to the decent interface, it's fun, not work!
At this price, you can't lose. If you like war games and particularly smaller scale action, you'll love this game. Set some tanks on fire!