You should go get the demo and play it fifty times.
Though all of the above is true, Far Cry 2 is boring and repetitive.
Most of the time you will use traveling until you engage a roadblock. For each mission in the game you will run across an average of 3 to 5 roadblocks with and average of 3 to 5 enemies you will have to kill to get past it.
When you travel back to get another mission you will discover that the roadblock you just wiped out have re-spawned as soon you left them out of sight, zzz.
I can't imagine why anyone would do all the effort of putting such a beautiful game together, with so much potential to it, and then leave it with a story that makes it so repetitive and boring.
You should go get the demo and play it fifty times. Just ad you own little imaginary story...