https://x.com/TNOQuoProQuid/status/2015872269482946858
Kudos to the STALKER games (at least the original X-Ray engine ones, haven't played STALKER 2 yet) for actually having wild animals that behave at least somewhat like living creatures and not killbots. Dogs (the regular, not pseudodog variety) will swarm you when in packs, but if you take a few of them out they'll start giving up and running away, and lone dogs encountered in the wild are pretty cowardly. Fleshes, being just mutated pigs, are generally pretty chill unless you get right up in their face. Boars are wilder, but it's kind of the boar stereotype that they're very aggressive.
Even among the more dedicated enemy mutants, like bloodsuckers, you still see them actually take advantage of their cloaking ability to maneuver around you and try to get good angles of attack rather than just charging in, and retreat when wounded (Call of Pripyat added a really nasty attack where if they catch you from the back they'll just latch on and straight up drink you like a vampire for massive damage, potentially instakilling on higher difficulties, so fighting them becomes this really cool dance where you have to somehow make sure you're always facing frontward an opponent that can become invisible).
I also hear good things about Rain World and its NPC AI
Rain World has some very fun AI and I can't claim it's "realistic" but it's definitely more vibrant than you usually see
I like that they didn't just do "player character vs everyone". The PC is just part of the food chain, and is viewed as a target or threat based on what else is around. It makes it feel really dynamic when the AIs are all interacting with each other instead of just idling until your character is in range
This is also something I appreciated in STALKER: Call of Pripyat - for the first two zones of the game, there generally aren't any human enemies who are immediately hostile. There's some bases where you won't be let in, but they'll specifically warn you on the radio to fuck off a couple times before actually opening fire (and one of those is actually part of a side quest where you can help them out and gain entry). Only by getting deliberately involved in the various faction conflicts as part of side-quests will you get to a point of some stalkers just shooting you on sight.
(Now of course, you are inevitably going to end up doing a lot of those side quests since that's where a lot of the game's content is, but still, even this small degree of other NPCs actually being reasonable rather than terminators programmed to hunt the protagonist is beyond what most games do, including the other STALKER games - Shadow of Chernobyl and Clear Sky very much didn't have this, with CS especially was heavily focused on fighting human enemies and forcing you into such faction conflicts as part of its main story. And the cool thing about this is that when you do eventually encounter enemies who are openly hostile, like in CoP's final zone, it feels all the more impactful - the Monolith faction ostensibly being religious fanatics in the lore doesn't really amount to much in gameplay in SoC and CS where they just shoot on sight like hundreds of other human enemies you've encountered up to that point, but in CoP it actually feels like you're encountering a whole new class of enemy)