This screenshot, included at Bungie's site in the collection for the Marathon Trilogy, which includes the Marathon Scrapbook and other goodies, is from a pre-release version of Marathon.

David "Candyman" Candland of Bungie in a netgame of Marathon. The weapon being fired at the player is the missile launcher. The weapon the player is using is the flechette gun. Introduced in Marathon 2:Durandal, the flechette was a fast-firing weapon that would work underwater, making it many times preferable to the MA75B assault rifle; however, ammunition for it was often scarce.

One of the most effective methods of combating the large, armored Hunters in the Marathon series was the Zeus fusion pistol. Remarkably similar to the plasma pistol in Halo, it had an alt-fire mode that charged up over time and fired one powerful projectile. This depleted the weapon quickly, but a few such blasts could take out a Hunter quickly. Interestingly, like a phaser in "Star Trek", if the alt-fire was held down too long, the weapon would explode and kill the user. An audible alarm beeps as you charge the weapon, faster and faster, until detonation.

Marathon Infinity extended the armed BOBs from Marathon 2 by giving them spacesuits, allowing them to fight in airless environment, hence the term "vacuum BOB" or "VacBOB" for short.

Marathon Infinity was particularly well known for its highly detailed and distinctive textures. Here is a multiplayer level featuring the so-called "Jjaro texture set" used in the game. The Jjaro, a mysterious, nearly omnipotent race that has disappeared from the universe in the Marathon series is widely speculated to be analogous to the Forerunners in the Halo universe.

Games in the Marathon series featured environments that were sometimes underwater, or, as in this shot, in vacuum. Only certain weapons, such as the fusion pistol shown above, would work in a vacuum; projectile weapons that depended on gunpowder like pistols and shotguns were useless. All the BOBs equipped for vacuum combat, like those above, toted fusion pistols.

Both Halo and Marathon have groups of aliens which are color-coded as a kind of indication of rank. The tall, armored Hunters of Marathon were no exception, although in the first Halo game it seemed as if there was only one group of Hunters (blue).

Automate drones like 343 Guilty Spark and the Sentinels were another item that appeared originally in the Marathon series. The first "security drones" in Marathon 1 were large, clunky, mechanistic devices. Marathon 2 featured much cleaner, organic-looking designs. Eventually the look changed even further, as seen above, with these dramatic, almost manta-ray like drones.

As in Halo, Marathon had several ball-objective games where the ball was represented graphically by a skull.

Many Bungie games from Marathon to Myth and Halo include so-called "ball" games, where the objective is not merely carnage but to control certain items. Usually while carrying them a player is unable to attack. In Marathon, as in Halo, these "balls" are represented graphically as skulls.

The SSM missile launcher in Marathon 2 packs quite a wallop; be sure to stay clear of targets to avoid splash damage. A similar weapon existed in the original Marathon game, but blocked considerably more of the player's field of vision, rendering it a bit less useful.

Marathon 2 was the first game in the series to feature underwater environments. Here the player is faced by a pair of flying security drones and a pair of the reptilian Flick'ta, indiginous to the swampy areas of the S'pht homeworld.

Not all BOBs are what they seem. In an attempt to confuse the player, some levels featured "simulacrums" that looked like BOBs, but were in fact a kind of proximity mine. Note the rather unnatural-looking yellow blood coming from the BOB on the far right. Marathon 2 used this feature, but it was present in the original game as well.

It should be noted that unlike other weapons, the Zeus Class Fusion Pistol will fire while underwater, but it will damage the player while doing so.

The moment where the Master Chief wielded two rifles in the E3 2003 realtime demo got a rousing cheer from the audience, but the Marathon cyborg did it first. Here, in Marathon 2:Durandal, we we see him fending off Hunters and Phfor Elite with dual shotguns, a very powerful combination.