It seems as though, shortly after the launch of Marathon, Bungie realized that it would need to take player feedback seriously if it wanted the new extraction shooter to be successful and retain players. One bit of feedback that repeatedly came up was the need for more PvE-focused gameplay. Initially, Bungie addressed this by adding the C.A.R.R.I. Protocol , which encouraged players to work together. On June 23, however, Bungie announced a series of key dates relating to new content coming to Marathon in the coming months. There are a number of changes and updates coming, including the new Cradle Evolution System which introduces a new way to reset player accounts in exchange for specific benefits and cosmetics.

More importantly, Bungie is introducing Vault Breaker, a new PvE play style that allows players to work together instead of fighting against one another. Vault Breaker launches in a major mid-season update to Marathon on July 21 and will see players take on a series of challenging vaults. Players can enter the Cryo Archive—a notoriously difficult endgame map—to play Vault Breaker in a crew, duos, or solo, and each run through the vaults will see players get progressively stronger as they face off against more and more powerful enemies until they reach a "mysterious entity" in the last vault. Instead of the loot-focused extraction shooter gameplay loop of traditional Marathon runs, Vault Breaker sees players leave behind almost all of their loot when they exfiltrate, except for Vault Data, a new currency that can be found in the Cryo Archives. Vault Data will be used to purchase upgrades for both regular kit and the specialized Sponsored Kit that is required to enter the Cryo Archives. The full announcement details follow.