From Halopedia, the Halo wiki
Brute Force is an achievement in Halo: Spartan Assault. It is awarded when the player finish the objectives using only the Brute Shot, melee and grenades in Operation D, Mission 1. The achievement is worth 10 Gamerscore on Xbox 360 and Windows systems, and 20 Gamerscore on Xbox One. It is represented by a circle with the jaws of a Jiralhanae inside it.
- If the player wishes to use the Brute Shot, they must first acquire it by killing a Brute Shot-wielding Jiralhanae with either melee attacks or a grenade.
- It is recommended that the player kill the Grunts with melee attacks, as they are easily killed, instead of wasting Brute Shot ammo or grenades on them.
- The player can ignore many hostiles on the level, instead focus on the mission objective of destroying the two sets of doors.