Editing Marathon Trilogy (section)

==Gameplay==
In the ''Marathon'' series, players can navigate futuristic environments in a first-person perspective. These environments are populated by hostile alien life forms or other players in multiplayer. Taking the role of a security officer equipped with energy shields, the player makes use of various firearms in an attempt to kill their opponents while trying to avoid getting hit by enemies' attacks.

There are two basic resources that the player must conserve to prevent death: shield strength, which decreases when the player takes damage, and oxygen reserve, which slowly depletes in airless levels and submerged areas. Wall panels located throughout the levels can be used to recharge shields or oxygen. Another type of wall panel called a "pattern buffer" is used for saving your progress. Ammunition and canisters which replenish shields or oxygen can be found while exploring the game's environments, as well as various temporary [[power-up]]s.

Single-player level objectives can include exterminating all hostile creatures, rescuing civilians, retrieving certain items, or exploring certain locations. Most levels contain platforms, stairs, doors, and liquids which players can control by activating switches. Some levels present players with simple puzzles where the objective is to find the correct switches to advance or to carefully traverse platforms.

In ''Marathon 2'' and ''Marathon Infinity'', the player can swim in different types of liquids such as water and lava; this slowly depletes the player character's oxygen and, for dangerous types of liquid, their shields as well. Another notable feature in all three games is [[Teleportation|teleporters]] which are able to send players to different parts of a level or to other levels altogether. They can also be used by the AI characters in the game to transmit ammunition to the player. While the player character is unable to jump, gravity is lower than Earth's, which allows momentum from rapidly-ascended stairs to carry the player upward. As with most games of the era, [[Rocket jumping|explosive weapons can be used to propel the player great distances]].

Many levels have a complex floor plan, made more complicated by the use of teleporters that connect different locations on the same level. As players explore a level, the areas they visit are automatically mapped, and the player can bring up this map at any time. The [[HUD (video gaming)|game HUD]] shows the status of shields and oxygen, the inventory, and a [[Motion detector|motion sensor]]. The motion sensor tracks the movements of nearby characters relative to the player, distinguishing between hostile creatures and allies. On some levels, the motion sensor is erratic due to magnetic interference. Weapons reload only when the current clip is exhausted. At any time, the player can swap their held weapon for another in their inventory; this includes gauntleted fists for delivering melee attacks, which do increased damage when running.

The game's story is presented to the player through computer terminals throughout the single-player levels; their textual content is often accompanied by annotated maps or other still images. The contents of these terminals most often consist of messages sent by artificial intelligence on-board the ship; these messages advance the games' narrative and provide the player with mission objectives. Other terminals contain civilian/alien reports or diaries, database articles, conversations between artificial intelligence, and even stories or poems. After all mission objectives are completed, the player usually has to find a terminal that teleports the character to the next level.

The ''Marathon'' games have five difficulty settings: Kindergarten, Easy, Normal, Major Damage, and Total Carnage. The difficulty level primarily determines the number and strength of enemies as well as the frequency of their attacks. Players normally can carry a limited amount of ammunition, but on the highest difficulty setting (Total Carnage), the player is allowed to carry an unlimited amount.

===Multiplayer===
The ''Marathon Trilogy'' received wide praise for its multiplayer mode. Not only did the games come with several levels specifically designed for multiplayer, as opposed to many contemporary games which used modified single-player levels, but the sequels offered unique game types beyond the standard [[Deathmatch (video games)|deathmatch mode]].

The host who gathers a game has many options available. Games can be free-for-all or team-based. They can be limited by match time or number of kills, or they can have no limit whatsoever. Respawn time penalties can be set for suicide-kills and for all player deaths. The motion sensor can be disabled, and the map is able to show all of the players in the game. Maps can be played with or without the presence of alien enemies controlled by the AI.

The original ''Marathon'' games can be played over [[AppleTalk]] networks (LocalTalk, TokenTalk, or EtherTalk [[LAN]], or [[AppleTalk Remote Access]]). Voice chat can be used to communicate with other players. Using the modern Aleph One engine, games can be played over [[Internet protocol suite|TCP/IP]] networks (LAN or Internet), with [[client-side prediction]] routines added to compensate for Internet latency and a new [[Matchmaking (video games)#Server browsers|metaserver]] interface for finding Internet games.

*'''''Every Man For Himself''''': This is the standard deathmatch. The winner is the person or team with the greatest score. A player loses a point if he dies and gains a point every time he kills another human player. This is the only game type present in the original ''Marathon''; Bungie planned on adding the ones included in sequels, but could not due to time constraints.
*'''''Cooperative Play''''': This style of play has players assisting each other to complete the single-player levels. Scores for each player are based on the percentage of aliens that they killed.
*'''''Kill the Man With the Ball''''': In this game, the objective is to hold the "ball" (a skull) for the longest amount of time. When holding the ball, a player cannot run or attack, but he can drop the ball by pressing the "fire" key. The motion sensor, if enabled, acts as a compass to point players in the direction of the ball. This mode was succeeded by the Oddball game type in the ''Halo'' series.
*'''''King of the Hill''''': Players try to stay located in a specially-marked area of the map pointed to by a compass in the motion sensor. The player wins who stays on the hill for the longest amount of time.
*'''''Tag''''': The first player to be killed [[Tag (game)|becomes "It"]]. If a player is killed by "It", he becomes the new "It". While "It", the game increments the player's clock. The players are ranked at the end of the game by who spent more time as "It". This mode was succeeded by the Juggernaut game type in the ''Halo'' series.