More General Notes
Tools and materials are readily available to those who want to look. However, the problem is the use of labor energy, and time. The most common reanimates have a sense of self preservation and thus can be actually scared off by sufficient resistance. Others are capable of probing and bypassing all the but the most stringent defenses, or even smashing right through them in the case of lambdas. Although the Planetary Citizens usually avoid picking fights, they have functioning armies if they so desire an area. Thus flexibility often wins over fortification.
Vermin patrol is a fact of life. The reduction in human exterminators, pesticides, and abandoned food stocks have lead to a explosion in their population, and the predators are still playing catch-up. In fact, quite often stores of supplies and food are better protected than the living areas. People can run away, and return when its safe again, but perishables can not.
Reanimates are not quite as brainless as zombies. Even the type ones have limited senses of self preservation and futility - they will avoid obvious traps, fire, and give up if it takes more than a few days to get to the target. Other types are smart enough to avoid laying siege all-together, waiting for the inhabitants to sally forth. Some Betas will wait for the defenders to be distracted with other problems, and actually sneak in if possible, or simply make a dash amongst other reanimates during a bigger swarm.
Seen from the air, the settlement looks like a humongous spider-web. Taking a cue from the VietCong in Cu Chi, they have covered walkways, bolt holes, and underground tunnels connecting most structures. Rather than hoping to weather an assault until it breaks, they actively encourage hit and run and active counter attack.
Not all arcologies are singular giant towers - some are more spread out, but still pack the population of a large town in a dozen buildings. The LS city state has reinforced a few of its structures against attack, and most of the others have turned the first floor into a series of ambush points, while constructing gates to block off access to higher levels. Thus in an emergency, most of the populace can be locked down while others form rescue teams to clear the problem.
Free City of Tesla
The city itself spirals around a hill, giving it the appearance of a ziggurat with buildings, wind turbines, and fluorescent tubes sticking out at odd angles. At the bottom is a steel-reinforced concrete wall, fronted by a deep trench crossed by retractable drawbridges. This is the closest any city-state comes to being an actual fortress, and part of this comes from the fact that much of the city is underground to deal with temperature extremes naturally.
The PC's settlements tend not be militarized, and are instead arranged in radial patterns out from a central military base. However, their territory in general is ringed with automated defense emplacements. The most visible of elements of such are the two variates of laser towers, though these are protected by missile batteries stationed somewhere behind them as a means to ward off attacks from a range beyond the laser's.
The Smaller of the two laser tower designs has five 1.5 meter (approx. 5 feet) kite shaped petals about the top, and can fire quite quickly and accurately. Its mostly specialized for anti-personal, light targets, or downing incoming ordinance. Its larger sibling has only three petals, but each is a bit over three meters in length, and can produce beams capable of searing aircraft aluminum from over a hundred kilometers with line of sight, and may be capable of intercepting orbital targets. Meanwhile, the missile batteries are some variety of vertical launch system with two stage missiles capable of rapidly reaching altitude, gliding to extend horizontal range, and then dropping the booster for maneuverability in the kill stage. It is at least equal to any variety humans deployed.