It feels like classic Resident Evil, the graphics and atmosphere are nice, the mansion is fun to explore (and, like RE games, the areas outside the initial mansion are less fun, but still fine), guns feel good to aim and shoot, etc. It's not a bad game.

The problem is that there are so many unintuitive things - puzzles where the solution makes no sense, things you're expected to know to do even though you'd never think to do it. And sometimes the UI lies to you, like doors that are marked red suddenly become "You were able to open it" with no indication to even check them again. (To be clear: not the classic "it was locked from the other side", just doors that were locked on both sides but now aren't)

A bunch of doors get opened at one point even though you didn't collect the key that matches those doors and it felt so underwhelming compared to, y'know, finding a certain key in Resident Evil games and being like "ooooh I can open those now!" (Turns out this is because some alternate route in new game+ does find that key, but in your regular playthrough they just randomly all become open)

The most bizarre issue: You collect "Spirit Essence" by beating some enemies, but the only things in the game that cost Spirit Essence either cost 100k of it (which you'll never get, it's some NG+ thing I guess) or 0. Like literally you just continually have to pick options of things that are listed as costing 0 spirit essence. Why am I collecting this stuff? And why are these uh "special" (to avoid spoilers) save rooms so often placed within 1-2 rooms of a normal typewriter save room? It's like they added those later in development but then didn't think to update their map design, so you have bizarre pointless save rooms everywhere. The map is overall not as well-thought-out as a Resident Evil game. Everything in those games' maps feels meticulously planned to force the player to adapt. In this game it's just like, oh, sure, that door is one-way because...??? Why did this key lead to a bunch of useless rooms and nothing else??? Etc.

The game is fun but the way I constantly described it while playing it is "You know how in Survival Horror, you usually have nice chill games where you can just go anywhere you want and not really ever feel any tension because you know nothing is going to happen?" That's Them and Us. So many times, you collect a bunch of macguffins, slot them in to some artifact to open a big climactic room, go inside, and... no, there's no boss, there aren't even any enemies that jump out! Backtracking is calm because you get enough bullets to kill everything. (On Normal mode over the shoulder. I've heard Fixed Camera is way harder)

The most annoying design choice, keeping it spoiler free, is that like 1/3rd into the game, you go visit a unique area, you get to do the first few rooms of it and start to solve a big puzzle room in it, then you get kicked out. As you keep playing the game, you find more paths that lead to that area, but they're blocked off with a cryptic message. I was waiting to find out how to get into them and continue that other area... Turns out all the doors are locked until NG+ and you have no way of knowing that! Why introduce that area and start the puzzle there if I can't even finish it?!

Also, the final boss got randomly stunlocked (I didn't do anything special, I just... shot him repeatedly and he just stood there and took 100+ bullets) though that was the only straight-up technical issue I encountered, the game runs fine.

This game is so close to me saying "Good Resident-Evil-inspired game, if you like Survival Horror then give it a try" but because of all the weird issues it has I'd really only recommend it to die-hard fans who can put up with those flaws. None of them make the game unplayable, they don't even make it "boring", they're just... annoying and weird. Even when it's not being annoyingly designed, it doesn't excel, like I said the map design and combat is just... average. It really goes to show you why the classics are the classics - You can copy their atmosphere and gameplay system but if your level design isn't as good, you can't capture the magic fully.