| Walker | 1 | ×1 | ×1 | 30 | The standard zombie, and most of every horde. Its health, speed and bite are the baseline everything else is measured against. |
| Shambler | 1 | ×1.4 | ×0.75 | 35 | Slower than a Walker but takes 40% more damage to put down and hits a little harder. |
| Runner | 3 | ×0.8 | ×1.6 | 25 | Sprints at 1.6 times Walker speed with a little less health. |
| Crawler | 4 | ×0.6 | ×1.1 | 20 | Drags itself along the floor. Low health, but it is small, low and easy to miss in a crowd. |
| Exploder | 5 | ×0.9 | ×1.1 | 20 | Blows up when it reaches you and when it dies, hurting anyone within about three metres. |
| Brute | 6 | ×4 | ×0.8 | 55 | A heavy with more than three times a Walker's health and a hit that takes over half of a fresh survivor's health. |
| Spitter | 7 | ×0.9 | ×0.95 | 15 | Spits acid from up to 14 metres when it can see you, instead of walking into your fire. |
| Armored | 8 | ×1.6 | ×0.9 | 35 | Riot armour halves the damage of every body shot. |
| Screamer | 9 | ×1 | ×1.2 | 25 | Its scream makes every zombie within six metres run faster for three seconds, again and again. |
| Toxic | 10 | ×1.1 | ×1 | 25 | Leaves a cloud of poison where it dies that hangs for five seconds and hurts anyone standing in it. |
| Frostbitten | 11 | ×1.2 | ×1 | 30 | Every hit it lands slows you down for two seconds. |
| Burner | 12 | ×1.1 | ×1.15 | 25 | Every hit it lands sets you on fire for three seconds. |
| Splitter | 13 | ×1.5 | ×1 | 30 | When it dies it splits into two Crawlers, each with 30% of its health. |
| Leaper | 14 | ×0.9 | ×1.35 | 30 | Jumps the last few metres at you instead of walking them. |
| Phantom | 15 | ×0.7 | ×1.5 | 30 | A pale, fast ghost with little health that slips straight through the rest of the horde instead of queueing behind it. |
| Medic | 16 | ×1.2 | ×0.9 | 20 | Heals every zombie within five metres by 12% of its health every three seconds. |
| Shocker | 17 | ×1.3 | ×1.1 | 35 | Every hit it lands stuns you for most of a second: no moving, no shooting. |
| Summoner | 18 | ×1.8 | ×0.85 | 25 | A robed occultist that calls two weak minions in through the windows, over and over. |
| Juggernaut | 20 | ×8.5 | ×0.7 | 80 | The boss of the late rounds: seven times a Walker's health, armour on the body and a hit that nearly kills. |
| Hellhound | hound rounds | ×0.55 | ×1.9 | 22 | A burning hound, almost twice as fast as a Walker with about half the health. They only come in hound rounds. |