Zombies

Zombies are the reanimated corpses of Humans, animals, and occasionally monsters.

Strategy
With Zombies it is important that very few of them have the ability to use range combat, even then it's usually the larger specimens whom simply hurl large rocks or explosive barrels.

Use range combat and avoid melee combat whenever possible, most are at their strongest when they can grab and bite at the player and present the risk of turning the player if they do.

If you do have to resort to melee combat, out of ammo or cornered, then having a powerful melee weapon at your side will help you get out of a bad situation.