Assembly and dissasembly are not the only things you can do. The firearms are fully operatable, you can learn how each one fires in different modes: automatic, burst (If the gun has the feature) and single fire. You can study how the guns work by deactivating some superficial features of the gun to show the mechanism and/or slowing down time to better understand the gun. You can also try to get the highest score amongst your friends.
This game is like your very own personal armory and includes assault rifles, sniper rifles, machine guns, submachine guns, pistols, revolvers and shotguns.
New weapons from all over the world will keep being added to the game for you to play with and experiment.