They really did go very in depth to the 'game controller', basically its a simulated DM for a TTRPG.

The ... constantly on edge thing?

Systems of spawning and nudging AI states of groups of enemies, specifically designed to make you feel that near constant tension.

That, combined with the entire group alerting/hording npc mechanic. Make a little noise? You might be ok. Make too much noise? Prepare to get fucked. Oh also, the threshold between 'probably safe' and 'totally fucked' is always moving around a bit, so... you don't really ever know where it is, with certainty.

Its basically an optimal way to induce a stress/panic disorder in a person, its not you watching a horror movie, its... you're essentially actually in one.

The other element of that is that they're much better at traditional map design, making choke points mixed with more open spaces, giving you some options to explore/use as cover/retreat to, but also, some of those options are actually traps that will punish you.

Ooops, that's not safety, its effectively a monster closet!

(Sometimes its an actual monster closet, sometimes its that the closet is actually fairly far away, but there's a prebaked navmesh path from the actual spawn point that leads directly to thst area you thought was gonna be safe.)

Also uh L4D doesn't have a 2D minimap.

It uses things like way points and object/objective stencils/borders, and, a lot of the maps are complex vertically, in addition to horizontally, so... just naively moving toward the waypoint?

Probably not gonna work so well in L4D, whereas in most games, that basically will work.

There is also a kind of problem in that a growing number of people cannot navigate their own hometowns without a real life minimap... players generally are getting worse at complex environment navigation overtime, and that's true in both real and virtual spaces.