Killzone: Shadow Fall ditches XP-based progression
Multiplayer progression in Killzone: Shadow Fall will not be based on XP, but rather on Challenges.
Completing these challenges, of which there will be more than 1,500 available at launch, will add points to your rank. This, in turn, rewards you with weapon attachments and enhancements to your abilities and visual identity.
Challenges in Killzone: Shadow Fall will range from "straightforward" to "very specific," according to Guerilla's Victor Zuylen. Example of the former is "Destroy 1 Turret," while the latter is "Kill 1 enemy player with Laser Tripmine while they are carrying a Beacon."
Elsewhere in the post, Zuylen discusses weapons and attachment, shields, combat honors, and many more multiplayer details.