Gameplay. A few of the things I liked to do is drag people from planes cars and helicopters.
Another fun thing is climbing buildings with a parachute and a grappling hook yeah I know: sounds ridiculous.
Another thing is driving my car over a cliff and watching the car spin around and around and around and then somehow survive the fall W.T.H.
There is plenty of play time: it took me over 14 hours to just get 27% of the game done though painfully I cant finish the game because when I finish the second last mission the game quits on me and I can't make a new profile!!!
Plenty of achievements to work on.
Graphics. Good detailed (realistic) graphics which is awesome: the scenic detail in the rocks, plants (shapes of trees), grass, roots, moving tree leaves.
Just Cause 2 has the best underwater graphics (again, the scenery: waving seaweed, starfish, shifting light patterns) I have seen though I haven't been underwater in many games. The character even appears wet when he comes out of the water.