I was thinking about sieges. The way the game works you can't really survive a siege. "IRL" (I know that sounds ridiculous) there's two reasons I can see for sieges happening. One is that you retreat to defensible terrain intending to at least whittle the threat down to numbers manageable for CQC or an escape attempt. The other is siege in an unwinnable situation in hopes of relief or a rational calculation that relief chances are safer than trying to fight through a crowd converging on you.
Can you do this? The first one, eh... if they don't bust down a door then I guess you could maybe try a fence-fight using an open window, minding that the window would have to have no barricade on it in the first place. A person could perhaps try fence fighting a window. Still, not really a siege, more like a specific tactical maneuver. The second one? I'm honestly not totally sure. In Zomboid no relief is coming. The world itself doesn't assume you're the Last Man Alive, the gunshots and screams prove you're not, but mechanically you are and you know it. No relief is coming. Can you outwait zombies? Will they give up? I don't know? I haven't tested it. But one big thing is that those barricades come down really fast, at least if there's a crowd that was worth holing up in the first place.
I was thinking the way sieges could maybe be fun is two different approaches, each a strategic decision. First is allowing spearfishing through incomplete barricades. Let me frame it this way: if the window is smashed/open and the window isn't totally barricaded, you can try to strike through it, obviously much more likely to achieve anything with a stabbing weapon. Realistically this does depend on the zombie being positioned to where you can try to strike, so it's a little random. This would feel like spearfishing: lurk by that window, wait, wait, try, connect or not. What makes this interesting is you pretty much have a math problem under duress. You have X entry points under pressure, each one will fail in a certain amount of time, potentially you can shore some of them up (I mean, potentially, "IRL" if you try to do this you're probably going to get a cold dead hand grasping on you but let's go with it), you think you can take down a zombie every Y seconds, do you believe you can whittle their numbers down fast enough that when a hole does open (how weak are my entries? how much pressure is on each? which fails first?) you can still manage the CQC.
The other is what I call a silence siege. This one assumes that zombies are not infinitely patient like Brooksian zombies, which Zomboid ones aren't anyways. A lot of this is overcomplicated, for sure, but the full version I imagine has it that the siege has an invisible timer on it. When the home comes under attack, their patience timer starts ticking down. Zombies are assumed to be creatures that are intelligent enough to respond to sound and sight as incentives (as gunshot events, generators, glass etc. suggest they are), but not intelligent enough to think in terms of "human isn't dead yet, he couldn't have left, so I wait forever." So they have this patience meter ticking down, and any time you make noise or do things that suggest motion (a shadow flickering by, say) it bumps it back up, and if they just straight up see you then it resets and of course they could always attack the barricades again.
So where does the drama come from? Inspired by UBoat, which was inspired by real life dramatics in the submarine war, you are running on "radio silence." Submariners had a very interesting problem that they could be heard easily due to the way sound carries through water; something like a man talking could give htem away, instantly, to a destroyer directly overhead. Not a problem until it is. Men would crack under pressure and get a sub depth charged. Commanders forced crews to live for hours under brutal, monastic-like silence, even trying to keep actions silent, to avoid giving away any signature.
This is life in a silence siege. A home has (this is where this probably becomes full moonshine, way too complex for a real dev) sound profiles, shadow profiles. Sound reverberates, sound carries. Does eating food out of a can make too much noise? Does the can opener make too much noise? If I creep into the kitchen, will I step on a floorboard and make it creak and draw attention?
A silence siege usually isn't a direct fail state, but little things pique attention, and you don't know how patient the zombies were to begin with, you don't know how well sound carries, may not always be aware of the sounds you make, and these things don't reset the patience but they do bump it up. Thus, you get attrition... like a real world siege. You have supplies. They have a willingness to wait out your supplies. Every time you fuck up in some little way, you have extended your stay in there. If you extend it too much, you die of starvation in your own home. The breaking of a siege is itself a moment of indecision. I imagine it as maybe that the zombies bang their fists against the walls even if they're not actively beating down a door/barricade in the moment. When the siege status lifts, they stop doing that, but that doesn't mean they're actually GONE yet. They're still zombies, they wander around. When you peak you're kind of gambling that enough of them have drifted off that what's left is manageable. You may just be firing the siege up again.
Can you control your circumstances? Yes. Sound-proof your home. Carpet the floor. Walk on socks (dangerous if the house does suddenly get breached). Carpet walls if you have to. Barricade up windows. This cuts off the possibility of a spearfishing fight, but spearfishing fights are kind of committing to it anyways, so you know... Hear a little creak in your house? Fix that shit. Hear a squeaky hinge on a cabinet? Fix that shit.
The goal: experience of paranoia. You can outwait them. You don't know how long it's going to take. You don't know if you're doing well enonugh. If you were attentive, as is always the case in Zomboid, you could have done better. But you CAN outwait the horde.
