Assault Ops

Assault Ops are a optional challenges featured in Halo: Spartan Assault and Halo: Spartan Strike, which can be undertaken in order to earn additional XP to spend in the game's Armory. Assault Ops typically require the player to kill some number of a specific type of enemy, using a particular weapon, vehicle or grenade. In addition to each of three mission-specific Assault Ops per level, a rotating selection of weekly Assault Ops was previously available, which could be completed on any mission. However, these have since been discontinued.

Two achievements are tied to Assault Ops; Extra Credit and Thorough can be earned by completing all of the mission-specific Assault Ops in Halo: Spartan Assault and Halo: Spartan Strike respectively.