If you want realism then you have found the perfect game!
The Graphics: The graphics compared to the games of today is really bad. However if you keep in mind that this games is stunningly SIX years old then you realise that the graphics isn't that bad afterall. In 2001 I promise you those graphics were really good although maybe not top notch even for 2001. The graphics is a little bit square'ish but the colours are truly great. A little pale and no shining colours which gives you a perfect atmoshpere in the game. It really feels more like a simulator then a game with these graphics.
The Gameplay: What really makes this game worth buying is it's gameplay. At the moment I haven't seen a game that could make you feel like a real soldier more than OF. Realism is the keyword for this game or simulator that I prefer calling it sometimes.
The sound: This might be the weakest part of Operation Flashpoint I'm afraid. The sound is functional but not much more than that and sometimes the voice acting get's a little bit boring. However the rest of the game really makes up for this part.
Lifetime: The cold war crisis campaign is long and does not end right away. More to it. You can actually play thru different paths in the campaign depending on how good you manage to solve the missions. In the end there's actually two different endings also that depending on how you manage as a soldier. Now you can also buy two more campaings. One where you play as the resistance leader and one where you see everything thru the russians side.
In conclusion:
If you are a shooters fan you should try before buy. If you are a realism fan then you have not much choice but to buy this super realistic game.