Really fun hunting simulation! Definitely not the run-and-gun Call of Duty/Battlefield style game, you need to stalk your prey and take advantage of the environment in order to sneak up close enough to get a good shot. Shot placement and ammunition type matters in this game, you need to hit a vital organ (lungs, heart, spine, brain) in order to get a clean kill. If you miss your shot, you'll have to follow the animal's tracks (or a blood trail in some cases) to catch up with it elsewhere. It's not a very fast paced game, but I found it very relaxing!
The AI for the animals is rather simplistic, they tend to hang out at different "eat", "drink", and "sleep" waypoints at different times of the day. You can use calls to lure the animal to you, but it works on bucks/bulls 100% of the time if they're within ear shot. They dumbly walk towards you when you use it, never really acting suspicious at all. I think that to some degree they decided to dumb the animals down to make the game easier. If they were to skittish, it would be more of a hiking simulator than a hunting one.
Some people have reported having issues with the game becoming unplayable after 30 hours or so. I have not encountered this issue and I'm running Windows 8 on an MSI laptop.