I've spent ~50% of the time messing with physics, using C4 to launch pickups full of bodies off the side of cliffs. You know, normal stuff like that.
The story mode is decent enough but side missions get old.
Love the ability to travel by air. That wonky, jerry-rigged, bare-bones helicopter is something else. Actually, it's more like a flying seat than a helicopter, but useful as hell.
Interaction between humans and animals and animals themselves is a nice touch; makes for some cool viewing.
I was dicking around, trying to drive a pickup through dense trees and plants as fast as I could without crashing and, at full speed, in the course of 1-2 seconds, I suddenly see a deer leaping out of some thick brush right in fucking front of me and running full speed at an angle towards me, and right behind it I see that cougar thing. I wince. Amazingly, the deer is spared from being blown the fuck up by the truck by a hair and the cougar just takes it almost square on. I didn't even have time to react. At first I laughed, but then I felt kind of bad.
The game is fun, no doubt. Feel like it's warming me up for Just Cause 3.