The game is a marvelous sandbox, it's big, open and it's beautiful. It's similar to car simulation games, except you don't have to deal too much with the inner working of vehicles. Driving the vehicles is very enjoying, especially when you are in the mud.
I've never seen such detailed and good physics before, it makes GTA V, Half-life 2 physics look childish. The mud looks superb, terrain transformation is very real, better than anything I've played, ever. The water gets dirty as you drive through, and the dirt slowly settle as you leave. The terrain does not forget what you did to it, and it's brilliant.
The graphics is top notch, one of the best in simulation games I know, and probably the best.
The catches are quit a lot, though. The tutorial is very limited, it will not teach you everything you need to know. Gamepad support is only partial, and awkward, so you need to use use mouse too. Keymapping in gamepad is bad, yet it does not allow you to change. It's difficult to handle the camera and most of 1st person view is outside the cabin.
Overall, I enjoy the game very much. If you have patience, I would definitely recommend it.