Regular Walker
No extra abilities or speed, health tied to the level of the mission.
Vulnerable to
Melee
Heavy Walker
Very large walker, moves slowly. Bodyshots are less effective than against other types of walker. Can take lots of shots before going down.
Vulnerable to
Assault rifle
Armored Walker
Slightly larger than Regular, with slightly slower movement. Their body armor soaks up a lot of damage, making them hard to takedown.
Vulnerable to
Sniper rifle
Slim Walker
Smaller size, faster movement. Amount of health is less than Regular.
Vulnerable to
Pistol
Grenade Walker
Vulnerable to
Shotgun
Spiked Walker
Vulnerable to
SMG