Still chugging along in The Walking Dead: Saints & Sinners. Save for the best in the Resident Evil series it might be my favorite zombie game (I'm probably forgetting of some cool game that should be above this but whatever, it's how I feel at the moment). And I've not even watched the series it's based on (or rather read the comic book or whatever, since that's the license they have, not the TV show, hence the cartoony visuals, but trust me it's still super immersive and scary in game regardless, I literally HATE indoor locations, they're so dark and creepy, I just spent a game day in a ruined gymnasium looking for some folks but I apparently went so slow and inefficiently I found none of them before nightfall and will have to return another time, lol). Now, sure, it's not a big open world game (though it does have some elements that you could say are light RPG aspects) or something but it's not on rails either. It's very clearly low budget but the developers cleverly worked around their limitations to make a very compelling game. I didn't even mind having to loot junk to craft more of my deteriorating weapons and items with, it felt natural and satisfying and necessary for survival.
The world is segmented in micro areas you can choose to visit and explore at will, you visit one such area each game-day which lasts like an hour or less, I'm not sure as I haven't checked the time while playing, it's so engrossing, and you may do a story mission, a side mission, a loot run for crafting materials, or all at once if you're quick and efficient before night approaches and the endless hordes arrive forcing you (and every NPC in the area, so any dialogues and missions you didn't go through are gone forever) to leave whether you achieved your objectives or not. Then you go back to your base and see if you can progress the story, maybe unlock new areas to visit or craft something new (or the same old stuff because yours are about to break or you used them up) depending on what you were just doing and repeat the process after a good night's sleep.
Generally you play at your own pace with your own priorities, to advance the story by going after a primary objective or better your situation in terms of crafted weapons and survival items and upgrades by visiting the corresponding locations. The main story is pretty linear with certain points you can alter its course by choosing who to ally with and beyond that you just play how you want, side and main missions may also have 2 or 3 different ways to go about them (well, one of these "ways" is to be a psycho and just kill everyone so it hardly counts I guess, you don't finish a mission, just raze and pillage, lol, but if that's your goal then it's not a bad thing, you didn't feel you missed out on a mission, just that you could care less about these people so screw them, but some times you stand to gain a lot from seeing it through) but nothing too complex, it's not an RPG just as Resident Evil wouldn't be an RPG if it merely added a simple skill tree and some branching paths to its story (actually, some have had slight story alterations based on what you did before anyway) or random factions to interact with in a couple different ways on your way to the preset ending(s). It kinda feels like a light immersive sim, simpler than most yet with the survival elements on top adding some more depth and persistence to the whole thing as you can revisit areas and they're repopulated to a degree but the mechanics support that well enough.
The interactions with the zombies are unparalleled though, the very first zombie I encountered got me very nervous as I wasn't sure how easy it would be to deal with (I think) a screwdriver. I got used to the wandering undead figuring out they're fairly easy in low numbers, you can grab them and push them into each other to make space and gain some time, you can hold one in place and drill its skull or attack another that is incoming with your free hand or whatever, I barely paid attention to them beyond using simple stealth mechanics to avoid them or if they're in an area I need to get to/through almost effortlessly killing them, only minding my use of the available resources in the meta game, mostly with melee weapons which require stamina to wield and a pistol ready in case something unexpected happened and I needed it for back up despite the noise it will make.
Then the game switches it up with adding the occasional human enemy which can be quite lethal when you're used to brain dead zombies, they don't necessarily attack you unless you get in their turf (again, the AI is very simplistic like something out of the original Deus Ex as they strand around or wander and also fend off zombies or hostile faction humans approaching their areas giving the world a more alive feel, but don't expect some crazy tactics on their part, they basically stand their ground and shoot or beeline to their target, still, overall it's effective in the game) but some times mission objectives require you to do just that (or you just wanna see if they have any good loot for you and become a mass murderer), as well as infected zombies that decrease your max health even if you kill them if they're too close (so melee weapons are a no go for them unless you get good at throwing them well enough to drill their skulls) and you need medicine to recover rather than just bandages and food recovery items you crafted as before. Then it also twists the undead around, now you have zombies with head protection making both ranged and melee kills much trickier to achieve as well as higher numbers of them. All the while adding more options and tricks to your arsenal, from melee weapons to ranged weapons to survival gear and distraction or explosive items and some upgrades like larger inventory or more max health and stamina.
It's hard to put into words. Maybe it's kind of like Zombi(U), except really good and well designed with more survival aspects (but it's not a drab sandbox, it's all about the main campaign which takes like 10 or 15 hours to finish so average FPS adventure length I suppose, it's a very condensed game with little padding - though you can pad it yourself with loot runs it's not even advisable, as more days pass there are less resources to find and more zombies or something, it doesn't get too bad and you can also find better loot later on in various ways but maybe it can unbalance your game if you get ridiculous with it early on, I dunno). It has LOTS more awesome details in its systems but they were so cool to discover happening during play that I don't wanna spoil more, I was editing one in just now but I kinda already said too much maybe, haha, trust me, play this, it's good.