"Body's still warm... must've been the wind."

It would actually be amazing in a stealth game for characters to call you out if you flubbbed a stealth/disguise/impersonation check.  "Nice hat, buddy!" could be your cue to slip into a side room and fix your disguise. 🙂

My favorite NPC reaction was when I was looking around in the Boneyard and spoke to an NPC named Avellone. He asked me what I was looking for. I told him "Good writing in Fallout 2." He responded by saying he didn't appreciate "wise guys" over there and told me to buzz off.

On a bit of a tangential subject, one curious and funny thing I noticed recently is the fact sometimes when you "interact" with an NPC, they usually are the ones to speak first, rather than the PC, prompting a conversation, even in more modern RPGs that are fully voiced. I mention that last bit because I can see it being a time/money-saving technique to assume the PC talked to the NPC if they don't have a voice to begin with, but it's not the case with fully voiced games. Thus, it's like they're talking to you on the basis of you staring at them hard enough, alone. Hahaha.

Oblivion needs to be studied for this: NPC reactions and interactions that are so bad they're good and are a massive part of the experience.

I may not be a programmer but I just want to say thanks for uploading these. I use them to understand problem solving.

"Hands off, sneak-thief!" Wow! How did YOU KNOW my sneak skill was so high!? It's like if guards ran up to you to force dialog to tell you "I didn't see that pickpocketing you just did, but I'm watching you!"

It'd be pretty fun to have NPC reactions in the typical fight/sneak/talk RPG setup, where on the sneak path they know big events happened, but don't really know who did it (or blame/credit who you might've pinned it on). So the ego stroke is from NOT getting the praise.
I still think Deus Ex does one of the best examples of reactivity based on what you do in the game. Like in general, bad guys will shout out "It's Denton! Remember the briefing!" or other lines like that when they spot you the further you get into the game, while early on they just call you a pig or a fascist. But also your choices you make impact the story a bunch in friendly locations, so they did an excellent job mixing up reactions.

Hannibal complimented that politician lady's shoes and he was scary enough...

The pulse for the NPCs, I treat it like a LOD, the mental LOD of the NPC.

Not to dive too deep into technology that only allegedly exists (and before watching the video!), but in some of the updates pushed to Valve's upcoming game Deadlock (which is in an invite-only beta, but is public knowledge, can be streamed and discussed without consequence, etc), there are references to "NPC Mood" as an influencing value for a project codenamed 'HLX', which many people very seriously believe is Half-Life 3.
Now, I'm not going to linger on the speculating about half-life thing, but I will say that organic NPC interactions and reactions are a huge part of what makes VR games feel so... artificial? I can point a gun straight at someone's head, hold it there, and they really don't care. Making a system like that would be a lot of work, no doubt, but for a big name like Valve, I hope this is one of the frontiers they're seeking to innovate on. The 'mood' system seems like a good fix for this, especially for Half-Life, given that the series started with a game where you could kill damn near everyone if you REALLY wanted to. By having NPCs be influenced 'emotionally' by player decisions, dictating their 'mood', it becomes way easier to make a character get sick of Gordon holding a gun to their head and get him out of their way. This adds WAY more, in my opinion, than any shallow GenAI NPC could, because it can be fast, responsive, fluid, and comparably inexpensive to a neural network.
This makes me really hopeful that we'll see more dynamic NPCs soon. It has almost always been the single biggest reason that VR campaigns like Bonelab feel strangely hollow to me.

wolves hunt in packs!

I always thought the fuzzy pattern recognition from something like Left 4 Dead would be helpful for avoiding these inconsistencies. Instead of forcing a line, ask if there's an appropriate line available matching world and NPC variables.

love the videos Tim stay healthy!

I’m half way through the video and idk if Tim mentions this but one thing about NPC reaction for me is that they also react physically or do things other than just talk about it. Example: “your helmet is scary!” backs away

Another example is consequences of reactions: “put some clothes on or I’ll report you to the guards!”

And maybe they get the guards and now you have to deal with that 🤷‍♀️

I saw a mudcrab the other day. Horrible creatures.

I don't care about getting my ego stroked. I want to feel like the characters have thoughts and personality outside of when addressed directly.

12:27 Trying to blend in with the locals Agent Thornton?  Good fieldcraft.

Note to self:  buy necropants.

I know you mentioned power scaling, but this question is notably different:  What are your thoughts on characters, classes, and builds that are powerful early game but stagnate or get worse as time progresses compared to ones that start weak but become notably better near the game's end?  Sometimes, this is a bug.  Other times, this is a feature.  What are the main contributors to this?  When is this style of play and design desirable compared to not?

For example, Fallout 1 had Energy Weapons and Big Guns which were useful, but mostly in the endgame.  Compare this to Small Guns which were generally useful throughout.

Another comparison is the Linear Fighters, Quadratic Wizards trope:  Non-casters tend to be great early on since they're steady in what they do and can keep going so long as they're healthy.  Compare this to casters who tend to have spiky effectiveness in short bursts because of spell slots, MP, or other limiting resource which becomes less limiting as the game progresses.  In D&D 3.5, a low-level Fighter can keep swinging if he's healthy, whereas a Wizard only has a small number of spell slots before he start cosplaying as a Commoner with a spellbook.

Thankee!