Either give an existing zombie type the ability to open doors, or create a new one, a more intelligent zombie creature, if you will. Of existing zombie types I was thinking maybe zombie master, necromancer, or feral predator - a type that’s relatively uncommon. Mi-go? Zombie scientist? Although scientists are kind of common. Labs might become problematic… or hilarious.
Or possibly this: For example create a copy of the child zombie monster type. Make it every bit identical, except it has the ability to open doors. Would there be conflicts? It would carry the identical name and graphic but it would certainly have different creature ID.
I suppose we should also then give the player the ability to LOCK doors…
Should doors have actual locks with broken/intact status?
But that would be just a tiny number of special cases.
The monster would need to want to go through the door, meaning that the player is visible on the other side or did something to attract zombie’s attention from the point behind the doors.
It would only really work well with vehicle doors and glass doors.
Considering that the sound a zed does banging on a wall/door can be worse than the zed itself, i don’t see the point balance-wise.
But lore-wise, a zed master should be smart enough to pathfind and open doors. Just for flavor, but flavor is important in cata.
But more than that, the door opening could potentially open the proverbial floodgates, allowing several other zombies to pass through. Closing the door behind you as you retreat is an effective escape strategy against any non-strong monster, but there could be monsters that bypass such pesky doors via other means and capabilities.
It’s more about setting a hundred of these 0.1% mechanics and traps that, when triggered, could start a snowball effect. It’s about creating exceptions to the rules. When a legion of these tiny exceptions exist in the same space, it tends to create havoc interesting experiences and stories about one thing leading to another resulting in a glorious catastrophy. That’s how Dwarf Fortress or RimWorld work in my mind. I guess on the other hand it could create adverse or unpredictable troubleshooting environment.