Just Cause 2 is a great improvement on the previous title & I would highly recommend it to anyone, especially for the price is selling it right now.
Causing Chaos the main objective of the game; blowing everything up is very fun! Helicopters are the boy! The graphics are superb (best water graphics of any game I've ever seen) & the upgrade system - whereby you can upgrade guns & vehicles is very addictive. The grappling hook adds a unique trait to the traditional shoot em up genre & is very fun! The story is pretty weak but the game is not linear & there is SO much to do to obtain the mighty 100%. Once you complete the main story, you'll only have completed about 25%-30%. The trophies are fairly easy if you're willing to put the time in.
The only negative is that the game gets slightly repetitive after you complete the faction missions & main story missions (not as bad as Just Cause 1 due to the added collectors trophies etc).
In conclusion, great game for the price; get involved!