He could see me take aim through my scope.
If we were in a vehicle together, he could see my characters head turn, and if I switched weapons, he could see my guy put away the one weapon to bring out another. If I was hacking a Bell Tower, he could see my character pop open the little box with my knife, pull out the wires, and flip the switch. We were just running around taking outposts and doing side missions, and it was amazing the level of detail and thought they put into co-op. I was expecting there to be huge lag issues, poor animations, etc. My buddy and I play co-op, and I gotta say, it was not only amazing, but totally blew my expectations out of the water.