simply, it's not fun.
Good graphics, fire fights, cars, huge open world, side missions,...everything is there; yet this game is simply not fun. you must keep reminding yourself "yes,It's a great game, It's a great game, It's a gre..." while trying not to get bored as you are walking or driving for miles through deserted jungles.
I advise you to find a more exciting game if "fun" is what you are looking for, but if you have lots of lots of free time, and you are really patient, and have already played all the better games, including even the 1st FarCry, then FarCry2 won't be a bad choice.