Remember the good ol' days when an FPS game was either World War II, Cacodemons or James Bond. Those were the days when heroes were simple, marines were not afraid to venture into Hell and multiplayer meant you actually had four friends. Those days were over the day a few employees of Medal of Honor started to veer off the pack and make their own World War II game.
(Let's Fast Forward)
Inifinity Ward decided to take their World War II recipe, add some modern combat, and create one of the most tried and true shooting formulas. Winner of multiple game of the year awards, MW forever changed how we classify shooters. Now every Tom, Dick and Harry has followed this formula to the T, making Call of Duty the grandfather of modern shooting.
And because they have created game after game, every shooter has to (is compelled to) follow these rules. Here are the unbreakable rules of every mainstream shooter.
Iron Sights:
Iron Sights makes a lot of sense, but it didn't make sense until Call of Duty made it a huge part of their gameplay system. Before that, Serious Sam, Max Payne, Master Chief and Duke Nukem would not be caught dead looking down their sights.
Every serious shooter now will not let you have accurate weapon firing unless you aim down your sight with the left trigger. It has to be the left trigger or gamers will change it or not play it. Even 3rd person shooters require aiming down the site (with the left trigger) in order to fire properly. Aiming down the sight, being the official way to shoot enemies, has affected multiplayer strategies immensely.
Regenerative Health
Technically, Halo 2 was the first user of the regenerative health concept. It should be noted that Bungie was making regen health in order for gameplay to be smoother and more arcade like. This kind of health system makes a whole lot of sense on a science fiction shooter where the player is wearing an armor suit.
And then Call of Duty decided to adopt it. Your flesh bound warrior could take multiple bullets in the chest and legs without feeling any of the effects. All he had to do was hide behind a box for a few seconds and he was good as new. This removed the scavenging and health restoration that were popular in every FPS game before it. No longer were your characters taking breaks to find supplies and get health, but now they were kicking down every door and going in guns blazing.
So many games have adopted that unrealistic health management system that it actually makes more sense to tell you the games that do not have it (I can only think of Resistance 3 and Singularity at the moment). This one gameplay quirk belongs next to the reasoning behind female armor logic and perks. Speaking of perks.
Rewards For Winning
Call of Duty made it official with Modern Warfare, if you win X number of times you get something that helps you win even more. They decreed that every multiplayer game from here on out must have recon planes, atomic bombs and drones as part of their quirks. Multiplayer arenas have been drastically "improved" so now every online game gives you some kind of reward for killing lots of people. Not only that, but this reward system is only for those who survive and don't die (though Modern Warfare 3 changed that).
This has had such a freeze on multiplayer shooters that rival followers of the Call of Duty method would dare not change the recipe. Doing so would kick them out of the proper shooter club and deem the game different."
Linear Gameplay
I remember when Medal of Honor Airborne was released and EA Games boasted that the gameplay was multi-directional and could be completed at the will of the gamer. It would replace that boring one direction gameplay and replace it with variety and decisions. Then Modern Warfare was released and it had all the great cinematic clinchers of a Steven Segal movie. Slow motion gun fights, nuclear explosions, bullets flying and people yelling pumped the adrenaline. Guess what? EA has yet to go back to a non-linear gameplay and is happy making their own brand of linear modern combat shooters. In fact, everyone is content with the linear gameplay. I am not saying Call of Duty invented linear gameplay, but there was a time when next gen games boasted in the open area and freedom of a shooter. Only the boring and uninspired games would be classified as linear. You could strategize in Rainbow Six or find secrets in Doom. That is no longer the cool thing. Now tight and confined spaces are hip in the shooter realm. Following the straight line of slow motion and explosions with a hearty chunk of scripted events is the cool way to go. Want to do some exploration? Nope, all doors are locked and your AI team mates get angry for you not following the mission. There are still open world shooters that force the gamer to use strategy, but they are not part of the Call of Cool Club.
Machine Gun Worship
This one element of shooting has forever tattooed that rhythm and feel of all popular combat shooters. This is the rule that all shooters must worship and strive for the automatic rifle. This automatic rifle must have a scope or an acog visual. A level without a machine gun or automatic rifle is considered foreign and outside the norms of gameplay. A shooter cannot survive on pistols, rocket launchers and shotguns, in fact very few games care very little about them compared to the machine gun optimization. automatic weapons are like the muscle cars of racing games or the star players in sports games, you would be really disappointed if they did not come in. Now a shooter must have at least ten different machine guns of various sizes, clips and feels or else it isn't a real shooter.
You may be thinking, "isn't that realistic how actual warfare works? Wouldn't it make sense to portray lots of machine guns." Yes and no. Yes there are tons of automatic weapons on this Earth, but the average American soldier has one rifle and one side arm. They usually only carry about 2 clips (about 30 bullets) and have to ration them off wisely. The idea behind picking up random rifles off dead bodies in warfare and each gun having 200 bullets is ridiculous. But it works and that is the unbreakable rule of shooters.
