Even if not worth it's predecessor, Far Cry 2 holds it's place in the history of shooters.
-Repetitive. The side-missions never differ. It's always the same thing over and over again, only thing that prevents it from making it boring is the astonishing evironment and the mindblowing action.
-No choices. When Ubisoft said you would be as free as the wind to work for anyone you want, and even to "betray" anyone you want, it was bull****, wich I found quite deceiving. Sure, you chose whom your first few missions will be for, but at the end, you're forced to go work for the other one then...they screw you over! Second Act, you work for the first one again (even though you betrayed them) then...you have to work for the other one once again even if they f****d you previously, surprise!
-Weak Story. The only good part of the story is the twist with the Jackal and the interactions you have with him, what happens inbetween (and there's a lot) is ... bland.
The good points:
Open World: They didn't exaggerate when they said it was open. You can take your mission however you want and it's great.
Action packed: The action never gets boring in the game. Even if - as mentioned previously - it gets repetitive, blowing up stuff with the grenade launcher is fantastic.
Visuals: Great graphics, probably only beaten by Crysis and Fallout 3 (even though I haven't played the latter yet)
Buddies: The Buddy system is great, even though if -- without giving away any Spoilers -- from my experience, your History with them means nothing in the end.