Bungie has opened up about how Expedition, the roguelite PvE mode coming to Marathon in the Symbiosis update, will actually play when it launches on December 8. The studio detailed the mode in a news post on its own site and a gameplay trailer released on November 10, calling it a “co-op PvE roguelite.”
Expedition is built around runs, and each set of runs is a three-run sequence of escalating challenges. What separates it from a standard PvE dungeon crawler is a system Bungie calls Flash Boosts: randomized modifiers that reshape every run, scaled to how strong the player’s gear already is. Their effects are tiered by rarity, and the high-end versions can change how a fight plays out, granting invisibility for a short time when a player takes critical damage, or a buff that triggers after a melee elimination.
Bungie framed the mode as “phase one” of a longer PvE plan rather than a finished product, a hedge that suggests Marathon players should expect the mode to keep changing after launch. The studio also positioned Expedition as a standalone experience rather than a pacified version of the extraction loop: instead of letting players run the normal extraction game without other players, the way Arc Raiders handles its PvE option, Expedition appears to be its own separate mode.
The mode’s content leans on a reworked Perimeter map. The playable zone is expanded with new points of interest, alien trees, and tunnels, and a new area called Reservoir adds a large main room with catwalks. Below ground, burrow encounters include a boss fight against the Tick Queen, while a giant crab boss has been added to the surface. New gear arriving with the update includes the Maverick hand cannon revolver, a V17 Flamethrower for area denial, throwing knives, and hack grenades, plus a new sword-focused runner shell named Bishop built around fast movement and blades.
For players who want PvP with less risk, Symbiosis also kicks off a beta for a 3v3 Team Deathmatch mode where a takedown does not cost you your gear permanently, a low-stakes alternative to the extraction loop. A social hub called Limbo rounds out the update, with a firing range and a dueling pit, a space Destiny players will recognize from the Tower. For Bungie, that is the point: the studio’s own Destiny 2 content unvaulting plan and this update are drawing from the same live-service playbook.
Whether Expedition can be tackled solo or requires a crew has not been clearly confirmed by Bungie: the studio’s materials say players can take it on alone or in a crew, but the question remains open.
Symbiosis lands on December 8 alongside a free-play week: Marathon is free to anyone from December 8 through December 15, including the new modes, and any progress and items earned carry over for players who buy the game afterward.
