Reloading is the act of ejecting an ammunition magazine from a gun when all the bullets inside it are spent, and replacing it with a new magazine full of usable bullets. Reloading as a mechanic is seen primarily in first- or third-person shooters, as a way to keep the shooting from becoming monotonous and un-challenging.
The first games to feature reloading were light-gun shooters, such as Operation Wolf, which automatically reloaded when bullets ran out, and particularly Virtua Cop, which forced players to manually reload their weapons. Time Crisis took it a step further by having players reload while taking cover, a feature that would not appear in other genres for many years. The reloading mechanic was then introduced to third-person action games through Resident Evil, which featured unique animations and different reloading times for each weapon.
On the other hand, early first-person shooters, such as Doom or Wolfenstein 3-D, generally had no such feature; players could fire any weapon continuously as long as they had ammo for it. The reloading mechanic was introduced to the first-person shooter genre by System Shock and later popularized by GoldenEye, which was heavily influenced by Virtua Cop.
Early games with the reloading mechanic generally made it simple: for example, in early light-gun shooters like Virtua Cop, reloading animations were rarely shown, while in GoldenEye, all weapons, from the meagre handguns to the grenade launcher, are reloaded with a simple animation where the gun is lowered off the bottom of the screen for about a second before returning, accompanied by vague metallic noises. Later games made reloading more cosmetically pleasing, as well as unique. In the Resident Evil and Halo series, each weapon has its own unique reloading animation, and reloading each weapon takes a different amount of time, with the pistol clip being replaced almost instantly and the rocket launcher taking several seconds. Indeed, more powerful weapons generally have to be reloaded more often and take longer to reload than weaker ones, as a balancing mechanic. For example, many magnum weapons are revolvers, meaning they can only be fired six times before they must be reloaded, and usually that the character must insert the bullets one at a time. A commonly-seen standout is the shotgun: in many shooters with shotguns, the weapon can carry several shells at once, but the reloading animation depicts the character replacing spent shells individually; the more shells need to be loaded, the longer reloading will take, ranging from near-instantly for a single shell to close to ten seconds if the "magazine" were empty.
In most games reloading is a simple static action, where you press a button and the game will automatically reload for you. However, recently some games have attempted to make reloading more engaging, with the possibility of weapon jams, and the Active Reload, seen in Killer7 and Gears of War. Despite its ubiquity in shooters, most games do not actually reflect a realistic reload. In most shooters, when you reload, it will simply refill the missing bullets for you, even if there are bullets still in the magazine . With a real gun, you would have to empty your entire magazine before reloading, or you would waste the remaining bullets in the ejected magazine. In most games today- even ones striving for accuracy- you do not lose bullets if you reload when your clip is half-empty. The few games that do this are considered to have Clip Management. While most shooters today feature reloading, a small sect of games still exist where you can fire a weapon to your heart's content until the ammo runs out. To name one, Stranglehold does away with reloading specifically to keep up with the constant firefight feeling of the Hong Kong action movies it tries to emulate.