RE0 is fine. Just fine. Other than the train, the environments are very standard for the series. Another mansion, another lab. It would all feel so safe if not for some head-scratching design decisions.
The lack of an item box means you're constantly shuttling your stuff between areas so you have it all on hand. A lot of the new enemies (the zombie apes, the leech men) take and deal a lot of damage. The last area introduces a frog that will eat your character if the other isn't around to save them. There's an awful bat boss fight.
I don't feel the game really justifies the two characters gimmick. It's neat to have someone around, but there aren't many puzzles or even bosses that utilize the feature in an interesting way.
The story is....odd. The villain is a clone of an old man made of leeches that controls other leeches through opera (but only in the train level?) He looks, and talks, like a finally fantasy villain, and his old and young versions have wildly different accents.
That said, I like the dynamic of Billy and Rebecca and I think they carry the game just fine. I find it very implausible that Rebecca went through all this 24 hours before the events of RE1 and reverted back to helpless rookie.
Honestly, I think the premise is fine, just not as a prequel. I didn't need an answer for how the Spencer mansion got infested, and I certainly didn't expect the answer to be "A man made of leeches did it."
Ultimately I think the game is just kinda forgettable.

Finally one of these Resident Evil lightgun games is an on-rails arcade shooter. I really wish I could have played this as intended on the Wii, but I think I made do with an emulator + mouse & keyboard. What you get here is a retelling of RE Zero, RE1, and RE3, each with additional scenarios showing untold stories of those games. Wesker escaping the mansion before it explodes, Ada escaping Raccoon City before it explodes, Rebecca's actions bridging Zero and RE1. It's some nice bonus stories because the retellings are pretty paired down.
The most egregious is RE3's levels which don't actually recreate any environments from 3 and instead reuse areas wholly from the Outbreak games, and not even the levels in Outbreak that are sourced from RE3. It's a version of RE3 where the game ends at the Police Department and Nemesis only shows up at the very end and sounds like a robot. Booooo.
There's a secret bonus campaign showing Umbrella's final days as Chris and Jill assault their final fortress in Russia. It's at this point that the game throws every non-zombie enemy in fat waves at you. I am no longer scared of hunter or lickers because this game had me slay 20 each just to walk down a hallway. They even reuse the bat boss from RE0.
There's a new Umbrella executive, Colonel Vladimir, who likes to lick knives. He's allegedly Wesker's nemesis in the company and works alongside the Red Queen AI, which I've been told is a character from the movies?
It was at this point that I was glad this was the end of Umbrella because they're no longer compelling villains. They were so much more threatening when they were a cold corporation looking to make a buck with dark experiments, but so much backstory has been laid upon them, with so many insane researchers and soldiers, that they're now a weird hybrid of eugenicists, PMC, intelligence agency, cult, and leech wizards.
As a lightgun game Umbrella Chronicles is fun. Your pistol has unlimited ammo, but you can scour the surroundings for additional weapons and heals, usually by destroying furniture. All the environments are destructible and it's oddly satisfying to blow up these familiar locations. Weapons are upgradable with the points you earn from ranks and eventually you can get every weapons with unlimited ammo.
Boss fights are annoying because they're based around targeting weakpoints and the camera just won't stay still on them for you to do any meaningful damage. The Plant 42 fight is especially awful.
If there's a standout mission it's the Umbrella Chronicles take on the 4th Survivor mission from RE2. Here Hunk's bloody escape from the RPD is overlayed with radio broadcasts from the desperate and dying citizens of Raccoon City.
If I wasn't so nostalgic for lightgun shooters I'd probably be harsher on it.

A better "The oppressed becoming the oppressor" ending than Game of Thrones

Operation Raccoon City is not a good game. It's riddled with bugs and reeks of a rushed development cycle. It's a sort of bizarre side-story to the events of RE2 & 3 where we're led to believe Leon and Jill were having frequent encounters with bands of armed Umbrella and US special agents.
It's a class-based 4 player game and as such probably falls into the vein of "fun with friends." Playing with AI means to play alone because the AI is braindead and on more than one occasion I caught them unloading their ammo into the adjacent wall.
To be honest, the game rides at about the C-tier for most of the missions because they're fairly inoffensive. It's fun to shoot hordes of zombies with automatic weapons and these are some gooey, destructible, zombies. It's the same enjoyment I'd get out of a Dynasty Warriors game. But the moment the game pits you against human foes with automatic weapons the game drops to the garbage tier.
Counter to your companions, the enemy AI is capable of placing a bullet between the buttcheeks of a flea at 50 meters.
A level will be going fine and then demand you progress down a hallway with no cover where 7 guys at the other end are doing alternating hails of bullets. Your health melts the moment you expose yourself in these sections and the game would only be a third as long if not for these roadblocks. It doesn't feel quality assured in any way. Dropping the difficulty did nothing to alleviate these sections and I wound up playing most of my time as the class with unlimited grenades, or the class that could turn invisible and run by all the dudes with guns
THAT ALL SAID, Operation Raccoon City panders very hard to RE3 fans especially, which I appreciate. You do whacky shit like orchestrate a conflict between Mr. X and Nemesis, operate the railgun from the end of 3, and potentially gun down Leon Kennedy and Claire Redfield. It's fanservice on fanservice and I feel quite serviced.
The environments are pretty moody and would be good in a better designed game. The sewer level has a great gimmick of there being low light so you have to chuck flares, which only illuminate how surrounded by zombies you are.
The game is bad, but it doesn't feel ill-conceived.
I spent most of the play time alternating between intrigue and ambivalence as even the frustrating parts slowly wore away into just something to expect. Maybe it's stockholm syndrome, but I'm not disappointed I played it

This game does a lot of things right. A lot. 85% of the time the systems work pretty flawlessly for an atmospheric survival experience. That remaining 15% are circumstances where random enemies take all your ammo to even stagger, zombies chain grabbing you becausee the animation takes so long, or Mr. X camping out in the hallway you need to go down. In these moments, I personally don't feel like I'm being forced into on-the-fly decision making, I feel like I'm seeing the numbers in the matrix and I'm waiting for the game to get back to that other 85%
I don't know. It's hard to articulate. I don't mind that it's hard, but it doesn't feel as satisfying to roll with the punches like in previous games. Every setback feels lethal in a way where I'm thinking about the time lost having to roll back to a worthwhile save.
There's also the disappointment at how much is copy/pasted between the two campaigns. It's hard to believe the the original RE2 did a better job at making the A and B playthroughs feel like different games, with actual compelling decisions.
I want to like it, but I simply wasn't having fun compared to RE4, or 7, or REmake 1