Operation7 is an MMOFPS, which puts much worth on realism. You can get out of small society, your own PC and friends.
You will encounter hundres of thousands of competitors in Opreation7 and you have to take them down or you will be. Operation7 is a free to play MMOFPS that has many outstanding attributes from any other FPS game.
You can also tilt to the side in order to shoot stealthily behind object. It is called Lean mode. It will make you move more flexible while shooting and hiding. Once you get used to lean mode, you can't escape from it.
Operation7 focuses on realism and provides 'It only takes one shot! One who aims first, kills first!' and for the most part this is true. In any map with open areas, it's vital to aim and fire from a distance since it is nearly impossible to survive long enough to get into close combat.