Editing Perfect Dark (section)

===Campaign===
[[File:Perfect Dark Gameplay.jpg|left|thumb|In this level, the player is aiming at an opponent. The game's [[HUD (video games)|HUD]] at the bottom right corner shows the player's remaining ammunition and the weapon's selected function.|alt=A long corridor with columns and girders on the right side. An opponent is standing in the distance. A hand holding a weapon and graphics symbols representing ammunition are seen at the bottom right corner.]]

''Perfect Dark'' features a [[Campaign setting|campaign]] mode where a single player controls the game's protagonist, [[Joanna Dark]], through a series of levels collected together into missions.<ref name="N64 review"/> In each level, the player must complete a set of objectives while opponents controlled by the game's artificial intelligence try to hinder the player's progress.<ref name="ONPG missions"/> Objectives generally require the recovery and use of high-tech gadgets like [[Night-vision device|night-vision goggles]] or door decoders.<ref name="N64 review"/> The player has freedom as to how to approach encounters and many objectives can be completed in a [[Nonlinear gameplay|nonlinear]] order.<ref name="Edge review"/> [[Stealth game|Stealth]] is an important element of the gameplay because the player can kill opponents without being seen or remain undetected by using disguises.<ref name="ONPG controls"/><ref name="N64 review"/> If Joanna fails an objective or her health is fully depleted, the player must start the level again from the beginning.<ref name="ONPG missions"/>

Each level can be played on three distinct difficulty settings.<ref name="ONPG missions"/> These affect aspects such as the number of objectives that must be completed, damage taken from opponents, the effectiveness of the game's optional aiming assistance, and the availability of ammunition and protective shields.<ref name="IGN Guide walkthrough"/> Four bonus levels may be unlocked by completing the campaign on each difficulty setting and all the challenges in the firing range.<ref name="IGN Guide assignments"/> Some of these bonus levels allow the player to assume the role of a different character.<ref name="N64 review"/> If all the levels have been completed on the highest difficulty, an additional setting becomes available, allowing the player to customise various aspects of the game's opponents, such as their health, aiming accuracy, and the damage they inflict.<ref name="IGN Guide walkthrough"/> The player may unlock [[Cheating in video games|cheats]] by completing levels within a certain time limit.<ref name="N64 review"/>

The campaign includes a [[Cooperative video game|co-operative]] mode, allowing either two players, or one player and up to four computer-controlled [[Video game bot|bots]], to tackle a level together.<ref name="ONPG missions"/> If two players play, the game [[Split screen (video games)|splits the screen]] horizontally or vertically.<ref name="Manual starting"/> Options such as [[friendly fire]] can be disabled and only one player is required to survive a level.<ref name="ONPG missions"/> A "Counter-Operative" mode is included, allowing one player to play a level as Joanna while another takes the role of an opponent while attempting to stop her.<ref name="NGen review"/> The player-controlled opponent has less health than Joanna but will reappear as another opponent when defeated. The opposing player may choose to take control of another opponent at any time by swallowing a suicide pill.<ref name="ONPG missions"/>