Cover system

A cover system is video game gameplay mechanic that allows a virtual avatar to avoid dangers, usually in a three-dimensional (and occasionally two-dimensional) world. This method is a digital adaptation of the real-life military tactic of taking cover to dodge enemy gunfire or explosives. Similar gameplay elements can be traced back to as early as 1986, in Rolling Thunder. Later games which refined the system include Bonanza Bros., Blackthorne, Time Crisis, Metal Gear Solid, WinBack, Splinter Cell, Kill Switch, Gears of War, Uncharted: Drake's Fortune, Mass Effect and Vanquish.

Definition
In gaming, a cover system lets a player character use stationary or moving obstacles to avoid damage. To be considered a cover system, there must be a physical interaction with the source of cover and the avatar. This means standing behind an object, as in traditional shooter games, does not qualify as a cover system, though some later first-person shooters such as Soldier of Fortune bridged the gap somewhat by allowing players to lean out from behind objects without fully moving their bodies away from protection. In addition, the player character must have the ability to move in and out of the covers' proximity, leaving points of vulnerability to the player. This discards the exclusive use of portable shields as a cover system, though they may accompany a stationary source of cover, as seen in video games like Army of Two, and Gears of War 2.

De-emphasized combat
Video games with cover systems tend to encourage players to avoid direct confrontation with enemies, but rather tactically manoeuvre to eliminate them. This also opens opportunities for cooperative games that rely on a partner to help a player manoeuvre around enemies. This is evident by games like Army of Two, which focus on cover-based cooperative combat. In Army of Two, an "aggro meter" was used to bring focus to one player, while allowing the other to easily sneak around cover; this is another example of using game design built around cover systems to change gameplay. Other games prioritize using cover only when necessary, such as The Club and 50 Cent: Blood on the Sand.

Enemy design
Cover systems have changed how non-player character artificial intelligence (AI) has been developed in video games. Fast-paced shooters have traditionally used weaker or less intelligent enemies to compromise with the player's inability to hide from them. This trend has changed with games using cover systems, with many using smarter AI to provide a challenge. Because players with cover systems are able to stay behind cover and fire at enemies without taking damage, many developers have created enemies that are able to take cover as well. This creates a need for the player to bypass the enemy's cover to attack them. This allows for puzzle elements, where developers place cover in strategic areas to allow the player to progress towards an enemy without taking damage.

Origins (1975–1998)
While not yet a mechanic, the idea of taking cover in video games is nearly as old as the shoot 'em up genre itself, originating from Taito's seminal 1978 arcade shooter Space Invaders, where the player's laser cannon could take cover behind destructible defense bunkers to avoid enemy fire. An even earlier example of the concept was Taito's 1975 shooter game Gun Fight, where the player characters could take cover behind destructible objects. The first games to show a rough cover mechanic were also arcade games, the first of these being Rolling Thunder, a two-dimensional run-and-gun game released in 1986 by Namco. This game and its sequels, Rolling Thunder 2 in 1990 and Rolling Thunder 3 in 1993, allowed the player to enter doors to hide from enemies and dodge their gunfire. An early video game that was heavily influenced by Rolling Thunder was SEGA's 1987 action game Shinobi and its many sequels, which allowed protagonist Joe Musashi to duck behind boxes/crates and featured more advanced enemy AI, where enemies could duck behind boxes, crates, and shields, to reload their weapons after firing or avoid/block Musashi's shurikens.

In 1988, Konami's Devastators, an early third-person shooter, featured a cover mechanic where destructible objects, such as sandbags and debris littered across the battlefield, could be used to take cover from enemy fire. That same year, the third-person shooter Cabal also featured a cover mechanic. Another 2D arcade game with a cover system was Sega's Bonanza Bros., an arcade action-adventure game released in 1990. Being a two-dimensional game, the ability to hide and take cover was used relatively easily and had only a few areas in which to take cover behind. In 1994, a cover mechanic was used in the game Blackthorne, which allowed the player to take cover by pressing against walls to avoid enemy fire. In Cabal and Blackthrone, the enemies also did the same, using cover to their advantage. These games were the first traces of cover systems used in video games, which would later inspire the same cover concept in three-dimensional console games.

The first 3D game with a cover mechanic was Namco's 1995 light gun shooter arcade game Time Crisis, which introduced a dedicated cover button, specifically an "action" foot pedal, that could be used to take cover behind in-game objects. This cover mechanic helped Time Crisis distinguish itself from rival light gun shooters, like Sega's Virtua Cop, and took advantage of the players' hand-foot coordination to create a new arcade game experience. While Time Crisis was a first-person perspective shooter, cover would later be largely bound to third-person shooter titles, due to cover freeing up the camera and for it being easier to judge space when the character is visible on the screen. Time Crisis, however, was able to use cover effectively due to being a rail shooter, where the path is already determined and there is no camera control.

In 1998, Konami's Metal Gear Solid for the PlayStation featured a cover mechanic, though its only function was to peek around walls to look out for enemies. Seeing as how the game was mostly stealth-oriented, the cover system served little combat purpose. Rather than a button, taking cover was initiated simply by continuously shifting Solid Snake towards a wall, instantly having him take cover. Metal Gear Solid is credited with popularizing the hiding-behind-cover mechanic. Splinter Cell, an Xbox game released after Metal Gear Solid in 2002, employed a similar stealth-oriented cover system.

Modern cover system (1999–2008)


The first 3D third-person shooter to include a closer-to-modern cover system was WinBack, released by Koei for the Nintendo 64 in 1999. Unlike other third-person shooters at the time, the game did not allow players to run-and-gun but instead forced them to stop and shoot, with crates and corners providing cover for the player character to pop out from and fire his weapon. In 2000, the arcade light gun shooter Police 911 introduced a unique cover system, where the player takes cover by physically ducking for cover (detected by motion-sensing technology) rather than pressing a button.

In 2001, Metal Gear Solid 2: Sons of Liberty featured a more developed cover system, with Snake or Raiden able to take cover behind walls, boxes or crates and pop out to shoot at enemies, while the improved enemy AI allowed enemies to also take cover from the player character. The enemies would often take cover to call for backup, and during battle, they would take cover then pop out and shoot at the player or blindly throw grenades from behind their cover. Both WinBack and Metal Gear Solid 2 also featured a laser sight mechanic, where a laser sight from the gun assists with aiming, which would later become a staple of cover-based third-person shooters. In 2002, The Getaway for the PlayStation 2 featured a similar cover mechanic.



Namco's Kill.Switch is credited as the first game to feature the cover system as its core game mechanic, and introduced the blind fire mechanic to the cover system. It was also the earliest third-person shooter that required a button press to initiate the action of taking cover. This was the only game at the time to allow the in-game avatar to lean out and shoot, vault over cover, or blind fire during the cover sequence. This cover system was nicknamed 'Offensive Cover System' (OCS) by the developers. While this was considered a change in the shooter genre, reviewer Ricky Tucker felt that the game relied too heavily on the cover system with little other gameplay focus. He also said that the game felt "more like a prototype than a game" and didn't see any outstanding moments for the game despite the innovative cover design.

In 2005, CT Special Forces: Fire for Effect featured a cover system inspired by Kill Switch. Uncharted: Drake's Fortune, released in 2007, also began development that year, and took inspiration from Kill Switch for its cover system. In 2006, several shooters featured Kill Switch-inspired cover systems, including Tom Clancy's Rainbow Six: Vegas, a first-person shooter released in November that switched to a third-person over-the-shoulder view when initiating cover, and Killzone: Liberation, a third-person action game released in October. Other third-person shooters to feature a cover system that same year include WinBack 2: Project Poseidon, released in April, and Ghost Recon: Advanced Warfighter.

The most famous among them, however, was Gears of War, released by Epic Games in November 2006. It was a third-person shooter focused entirely on cover-based combat. While not the first to use a single button for moving in and out of cover, it used the mechanic more effectively with environments specifically designed with the cover system in mind. The cover system was considered revolutionary at the time and was credited with the massive success and sales of the game and its sequel, Gears of War 2. Its cover system was inspired by Kill Switch, whose lead designer was employed by Epic Games and was involved in the development of Gears of War. In turn, Gears of War inspired a new wave of video games using the third-person, single-button cover system. Games such as Grand Theft Auto IV, Mass Effect, Quantum of Solace, Harry Potter and the Deathly Hallows: Part 1, Harry Potter and the Deathly Hallows: Part 2, and others, use similar cover systems. According to Stuart Lindsay, some games' cover systems are criticized because the cover system is created as an afterthought rather than the game being built around that feature.

Recent developments (2009–present)
After the video game cover system was popularized, several recent games have attempted to alter or further revolutionize the cover system in a unique way. One such game is the first-person shooter Killzone 2, which utilized a complete cover system that was used in the first-person perspective the entire time. Other first-person shooters like the Rainbow Six: Vegas series have traditionally changed to a third-person view when taking cover.

One of the ways that games have changed can be measured by the fact that video games been shifting the focus from participating in combat from behind cover to only using cover as a last resort. An example is 50 Cent: Blood on the Sand, which rewards players for assaulting enemies. Uncharted 2: Among Thieves uses cover abilities by allowing the player to hang onto cover vertically and use three dimensions of cover to avoid enemy fire. Dark Void uses a 360-degree threat radius, as the player character can fly. This is accomplished through vertical cover like scaling a mountainside or standard cover like walls.

Vanquish, a 2010 third-person shooter developed by Platinum Games, is regarded as the most successful attempt at reinventing the cover system, which it has been credited for taking "to the next level." In contrast to previous cover-based shooters, Vanquish has bullets and missiles coming from all directions in a manner reminiscent of bullet hell shooters and cover is easily destroyed. Often a single shot is enough to remove the player's cover, forcing the player character to be on the move, while the game also penalizes the player on the scoreboard for the amount of time spent in cover. Its most important innovation, however, is the slide-boost mechanic that allows the player to slide-boost into and out of cover at high speeds (sometimes in slow motion using bullet time), acting as both a defensive escape and an offensive setup, opening up new gameplay possibilities for cover-based shooters and increasing the pace significantly. According to director Shinji Mikami, the sliding boost mechanic was influenced by the 1970s anime series Casshern. Vanquish has since set a new trend, with its influence seen in recent first-person shooters that have incorporated similar slide-boost mechanics, including Bulletstorm, Crysis 2, Ghost Recon: Future Soldier, and Killzone 3.

Reception
The cover system has become a large part of modern gaming and has changed the third-person shooter in many ways. Nate Ahearn of Yahoo! News felt that the only types of shooters today are those with cover systems and those without, noting that this was not the case in earlier gaming generations. He felt that cover systems changed the game experience for the better and that including a cover system in a game improved it. Ahearn reasoned this by claiming that cover systems were so vital because they allowed the player to view the character, creating a deeper connection between the gamer and the player character. In addition, Ahearn felt that having a cover system allowed the game to slow the pace and "really lets you flex the muscle of your fancy new graphics engine", giving games with cover systems advantages over fast-paced shooters.