We humans are pretty good at building gates to keep people out. We've been doing it for a long time for military purposes and to stop thieves.
Why Do We Have Gates?
Because there has to be some way for friendlies to get through the defenses while keeping the bad guys out.
From a military perspective, a gate isn't there to stop people from getting in. They'll get in. Instead, it's there to channel them into a particular area by the allure of an easier passage. Avoid the wall and its defenses, drive through the gate! In anticipation, that particular area is set up as a kill zone: a deadly crossfire will be in place to mow down anyone who comes through, combined with removable obstacles to slow them down and pin them in the kill zone.
From a security perspective, a gate is also there to slow down a thief. But instead of a kill zone, it exists to be such a nuisance to force the thief to give up, or to make so much noise getting through they're detected. Once detected, forces are rushed in.
So, gates exist to...
- provide access through defenses for friendlies
- herd attackers into a kill zone
- force the attacker to reveal themselves
- slow the attacker to there's more time to deal with them
Zombies don't act like an intelligent, coordinated military force, nor do they act like thieves. They just walk, slowly, towards food. They might not even find the gate and instead just walk into the wall in whatever direction they came from. (Note: I only watched the first few episodes of The Walking Dead, so I don't know exactly how their zombies act).
That is until you start making a bunch of noise going in and out of the gate. Then they'll go investigate. The problem is not having a big rush of zombies at the gate, the problem is having a slowly growing, constant pile up at the gate which is putting more and more pressure on it until, like a fence at a football riot, it will collapse.
Zombies also don't get tired and give up. They'll keep banging on that gate and walls until one of them breaks.
This means you need an active defense to clear the zombies off, and you need to do it efficiently and safely.
Establish A Kill Zone
Take advantage of that pile up and use it as a kill zone. The zombies will be easy pickings as they pile up against the gate, or even the walls. A few isn't a problem, unless you need to go out. Take care of them before there's too many.
Kill Them Cheaply
You want to set up your gate and defenses so the zombies can be killed without expending resources. This means no guns and no gasoline. There's going to be a lot of them, and you only have so many bullets. Save them for emergencies and foraging.
Kill Them Safely
You're going to be doing this a lot and even a single bite means you're dead. That means it has to be done very safely, no heroics.
Bars + Pikes
The simplest actively defended anti-zombie gate is some sturdy iron bars and a few people with pikes. Zombies thrash against the iron bars, the pikemen stick them in the face from well outside of arms reach. Cover the end of the shaft in grease to prevent the zombies from grabbing it. If they do, pikes are cheap. Let go and grab another one. Maybe you can get the lost one later when they're all dead.
These bars can and should be placed all around your defenses to prevent zombies from piling up at any point on the wall.
Against an enemy like a zombie, rigid defenses might not be the best idea. Instead, you might want to try a [flexible security gate] like you'd find in a mall.
Unlike rigid bars which will take all the force of zombies banging on it, a flexible security gate will flex and wobble which will absorb some of the impact. And they have those handy slots for stabbing zombies through.
Just make sure it's strong enough to hold back a horde pressing against it, and it's secured to something that's strong enough, too.
Evolution 1: The Murder Hole
This is, essentially, an inner and outer portcullis: a big, heavy gate with spikes on the bottom that drops from a height.
Zombies on the outside, pikemen on the inside.
P * *ZZZZ
P * *ZZZZ
P * *ZZZZ
P * *ZZZZ
P * *ZZZZ
Raise the outer gate, let some Zed in, then lower it again. If there's some zombies under it, so much the better.
P *Z *ZZZ
P *Z *ZZZ
P *Z *ZZZ
P *Z *ZZZ
P *Z *ZZZ
Now you can better manage the number of zombies you're dealing with at once. Once you're done, you can get into the inner area to clean the bodies up and avoid a pile up.
There's any number of improvements which could be made to this, for example a grilled platform on top, out of arm's reach, to stab down through.
Should the inner gate fall, you only have to deal with a limited number of zombies inside the wall. Should the outer gate fail, you have an inner gate to fall back to. This brings us to our next point.
Have A Mobile Backup Gate
Taking a page from The Road Warrior, use a heavy vehicle like a bus as a mobile gate. But instead of using it as your primary gate, have it ready as a mobile backup gate to close any breeches in the wall. Just drive it up to block the gap. This will plug the breech and give the defenders time to react.
Evolution 2: Dig A Pit, Fill It With Spikes
If the Walking Dead zombies are like the Romero and Max Brooks zombies, they aren't very bright and will happily walk off a cliff if there's food on the other side.
To make our murder hole even safer, we can add a pit filled with spikes.
Raise the outer gate, zombies fall into the pit and get impaled. It probably won't kill them, but it will immobilize them. Then stab them with pikes at your leisure. You can even throw a grating over the top to make the stabbing even easier.
Evolution 3: The Crushinator
You've got these zombies pressed up against your gate, you know where they're going to be, why not use it to your advantage? Scrape them off the gate with a heavy object.
You have a heavy door (optionally sharp) held above and just outside the gate. Zombies press against the outer gate. Drop the door right on their heads. Crush the zombies. Lift it again. Repeat until all zombies are dead or disabled. Finish them off with pikes. Safe. Efficient. And it's a spare gate!
Don't Have A Gate
Taking another page from the original Dawn Of The Dead, do you really need a gate? What about a ladder or ramp? Zombie attack? Retract the ladder. Just be sure you have a way of clearing the zombies off the entrance, like a set of bars to stab them through.
O | - O _(Brains)
|-o - o-|
| | | |
/\ | | /\
7 Days To Die is a "survival, horde, crafting game". It's Minecraft meets Left4Dead. It's a great place to try out various anti-zombie defense schemes.
What sets 7D2D apart from other zombie survival games is everything is destructible. Wood, metal, concrete, even the ground itself, the zombies will chew through it all. Any passive defense will eventually be ground down and fail. I've had zombies chew through concrete, wriggle through firing ports, climb over each other like ants, tear the foundations out of platforms, and even come up through the floor!
The other thing that sets 7D2D apart is right in the title: every 7 days, ready or not, you will be attacked by a horde. It lends a certain time pressure to everything you do. Grand plans give way to necessity. Are you going to try to explore to find the mixings for concrete and bullets? Or chop down more trees to bodge together more spikes and arrows?
Finally, while basic combat is rather simple, getting hit is brutal. Especially at the higher difficulty levels, one hit and you're stunned, two or three and you're dead.
The game is still in early access, but it's totally playable and totally brutal. Big changes are coming in Alpha 16 in March, so you might want to wait until then. But if you want to torture test your ideas about zombie defenses, give it a shot.
Here's the aftermath of a horde night in my fortified chateau. It took the "no gate" philosophy. All stairs were torn out, even interior stairs, and replaced with ladders and armored hatches. We attracted them to a particularly well fortified corner of the house.
That was four layers of spikes. Note the firing ports for an active defense. Also note the hasty repairs on the concrete; they got through, but that was just the outer defenses. We had multiple backups to retreat to.
This was just one evolution of the defenses.