Regular (Min. Mission Level 1): The most common Walker type. Their health is dependent on the level of the Mission. Weak Against - Melee Heroes.
Slim Walker (Min. Mission Level 2): Smaller than Regular Walkers, and move much faster. Lower health than Regular Walkers. Weak Against - Pistols and Pistol Heroes.
Heavy Walker (Min. Mission Level 6): Heavy Walkers are the biggest, and slowest. Bodyshots are less effective against the Heavies, and they can take a lot of shots to put down. Weak Against - Assault Rifles or Assault Rifle Heroes.
Armored Walker (Min. Mission Level 8): Slightly larger than Regular Walkers. Their body armor soaks up a lot of damage, making them hard to take down, but also slower than Regular Walkers. Weak Against - Sniper Rifles or Sniper Rifle Heroes.
Rotten Walker (Min. Mission Level 10): Smaller Walkers with regular speed. Weak Against - Shotguns and Shotgun Heroes.
Spiked Walker (Min. Mission Level 10): These Walkers are regular-sized and move at the same speed as Regular Walkers. Spiked Walkers are immune to headshots - aim low! Weak Against - SMGs and SMGs heroes.
Whisperer (Min. Mission Level 5): A member of a mysterious group that wears the skins of walkers to mask their presence. Moves fast and goes straight to the Player. Weak Against - Bows and Bow Heroes.