Game design 

Like most shooter games, first-person shooters involve an avatar, one or more ranged weapons, and a varying number of enemies.^[6] Because they take place in a 3D environment, these games tend to be somewhat more realistic than 2D shooter games, and have more accurate representations of gravity, lighting, sound and collisions.^[3] First-person shooters played on personal computers are most often controlled with a combination of a keyboard and mouse. This system is often considered superior to that found in console games,^[10][11] which frequently use two analog sticks, one used for running and sidestepping, the other for looking and aiming.^[12] It is common to display the character's hands and weaponry in the main view, with a head up display showing health, ammunition and location details. Often, it is possible to overlay a map of the surrounding area.^[13]

Examples of different HUD's and different styles of FPS games:

In the DARKNESS Jakie can use the Darkness as a weapon in the shadows

 In Left 4 Dead 2, player analyzes, his/her's surroundings to move the next location while taking down zombies/un-dead...

in SiN the player is taking a look at a construction site in the form of a puzzle/clue to move on...

Combat and POWER-UPS!

First-person shooters often focus on action gameplay, with fast-paced and bloody firefights, though some place a greater emphasis on narrative, problem-solving and logic puzzles.^[14] In addition to shooting, meleecombat may still be used extensively. In some games, melee weapons are especially powerful, a reward for the risk the player must take in maneuvering his character into close proximity to the enemy.^[15] In other situations, a melee weapon may be less effective, but necessary as a last resort.^[16] "Tactical shooters" are more realistic, and require teamwork and strategy to succeed;^[12] the player often commands a squad of characters, which may be controlled by the game or by human teammates.^[17]

These games typically give players a choice of weapons, which have a large impact on how the player will play the game.^[3] Some have highly realistic models of real weapons, including their rate of fire, size of ammunition, and accuracy. However, they may allow players to carry many of them at the same time, with no reduction in speed or mobility. Thus, the standards of realism varies between design elements.^[18] The protagonist can generally be healed and re-armed by means of items such as first aid kits, simply by walking over them.^[19] Some games allow players to accumulate experience points similar to those found in role-playing games, which can unlock new weapons and abilities.^[20]

^{A well known FPS would be Call of Duty 4 Modern Warfare, typically known for well known stories, simple multiplayer modes, usually gets 9's and 10's on the gaming review boards.}

^{typical tactical shooters come with a basic load out system I.E. perks, guns, med kits, riot shields, claymores, etc.}

^{most tactical shooters like Rainbow Six, or Star Wars Republic Commando will come with a Command system(issues order to A.I. units to move, breach and cover, take and hold, etc.)}

Level design

First-person shooters may be structurally composed of levels, or use the technique of a continuous narrative in which the game never leaves the first-person perspective.^[1] Others feature large sandboxenvironments, which are not divided into levels and can be explored freely.^[21] In first-person shooters, protagonists interact with the environment to varying degrees, from basics such as using doors, to problem solving puzzles based on a variety of interactive objects.^[1] The environment can be damaged, also to varying degrees: one common device is the use of barrels containing explosive material which the player can shoot, destroying them and harming nearby enemies.^[19] Other games feature environments which are extensively destructible, allowing for additional visual effects.^[22] The game world will often make use of science fiction, historic (particularly World War II) or modern military themes, with such antagonists as aliens, monsters, terrorists and soldiers of various types.^[23] Games feature multiple difficulty settings; in harder modes, enemies are tougher, more aggressive and do more damage, and power-ups are limited. In easier modes, the player can succeed through reaction times alone; on more difficult settings, it is necessary to memorize the levels through trial and error.^[24]

^Examples: 

In HOMEFRONT a helicopter raises a neighborhood. 

In F.E.A.R. the antagonist Alma walks and mentally terrorizes the protagonist. 

In Bioshock 2 the Little Sister walks ahead with the Big Daddy not far behind.

PART 3(final) COMING SOON!!!