From Halopedia, the Halo wiki
Foot Soldier is an achievement in Halo: Spartan Assault. It is unlocked by completing the objectives in Operation E, Mission 4 without using any vehicles or turrets. 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 two footprints inside it.
- Due to the high amount of enemy vehicles on the level, it is recommended that the player uses the rocket launcher or the Spartan Laser on the level.
- It is suggested that an automatic weapon is used for infantry enemies, and a rocket launcher or Spartan Laser is used against vehicles and turrets.
- The player can avoid most enemies on the level, if necessary.