One fun fact about me is that I am a massive Pokemon fan. To the point where ~15 years ago I actually played the games at a competitive level for real-life money, and I used to speedrun them to boot.
I really enjoyed Legends Arceus (planning to revisit it, might make a review later after I do so). I thought it was a great step forward for the series and genuinely was far superior to Scarlet/Violet.
X/Y are another one of my favorites, but (like Sword/Shield) they always felt undercooked. Game Freak clearly wanted to make a Pokemon Z, but powers from up high said they needed a new generation for the 20th anniversary and so they made Sun/Moon instead.
In many ways, Z-A actually feels like the Pokemon Z we never got. XY left a lot of plot threads open, intending for Z to finish them. Instead, Z-A picks up a LOT of plotlines from XY, acting as a straight-up sequel to a game that came out 12 years ago. My fiance (who never played XY) is playing the game alongside me; I feel the need to explain some of the plot points because the game sometimes acts like you finished XY yesterday.
And honestly - I love the lore. I love that we're getting closure on some of this stuff that was clearly intended to be wrapped up back in 2015. Pokemon can have some flimsy story; this time the story actually has a bit of meat on it. Is it groundbreaking narrative stuff? No, but it's a bit more interesting than "Leon saves the day when you aren't looking".
The game overall feels like it's a bit more mature. There's a lot fewer euphemisms than would be expected otherwise. The main character is an adult - good heavens! - and the battle system is something that wouldn't be as easy for a child to immediately grasp.
Gone are the days where you choose the super-effective move and mash A. Now battles are real-time and work as a bit of a dance - each move is on a unique timer, so you need to cycle between moves as they come up. But then each move has a wind-up time, and more powerful moves have a longer wind-up time. Moves also have a range, where your Pokemon sprints to an effective spot to start their wind-up animation. When cycling moves, you need to keep the position of your Pokemon and the effective range of the move in mind, while also hoping the enemy Pokemon doesn't move out of the way (which rarely happens, but does happen sometimes).
That being said - basically none of this is taught at all. You learn by doing. Which is somewhat annoying since it can be unclear why things are happening and why your Pokemon isn't doing damage.
The new battle system effectively turns the balance of the entire game on its head. Moves (and Pokemon!) which were once great are now garbage. Moves (and Pokemon!) that used to be garbage are now good. Generally there has been a flattening of the power disparity between Pokemon, replaced with real-time tactical decisions you make as a trainer.
Game Freak has gone so far as to remove abilities from the game entirely, which serves to make individual mons even more same-y: abilities added texture to different Pokemon, and now that texture is missing.
I'm not a fuddy-duddy. I don't think Game Freak should just make the same game over and over again and just replace the names each time (that said, I would still buy them). The shake-up to battling is certainly new and interesting! But honestly I'm not a fan.
Pokemon, to me, is a turn-based game. It does not demand quick reaction times; it rewards thinking through your options at length and choosing the best option for the current situation. (Yes, you can just mash A through the story because the story is made for babies; I'm referring to higher-level play when I say this.) Making a mistake is punishing; the game lives on being able to stay 1 step ahead of your opponent at all times. It is a game where you play slowly and meticulously.
Z-A is the opposite of that! It rewards button-mashing, high-speed play. The most tactical you get is in positioning. It plays similar to Hades (which I've been playing a lot of), just minus the boons etc.
The meta - if you can really call it that - is in sustain. Being able to heal yourself through lifesteal effects (Absorb etc.) will carry you through most battles. Being able to tank a hit is more important than being able to dish out damage quickly. But the game really loses something in the process.
Take Aegislash. Aegislash has a cool ability where it can change forms between an attack form and a defense form. Except in Z-A, it just winds up being put in its attack form and gets one-shotted. Which is a shame, because Aegislash is a cool Pokemon!
Mega Evolution is a focus of the game. In XY, Megas were a big deal! They changed the entire battlefield and were a presence as a big swing in the match. You only got one, and it had to be chosen before the match even started, so you have to make it count!
In Z-A, there are Megas out the wazoo. And because of that, the restriction of "one per fight" is gone, replaced with a meter that you charge up (think Limit Break). But as I mentioned, the new battle system makes all Pokemon kind of feel the same - and that includes Megas. Becoming a Mega is really just a model swap instead of a battle-defining moment. I'm happy that Megas have returned, but I wish the battle system didn't make them feel irrelevant outside of special canned battles where Mega Evolution is the only way to do damage.
Another thing about Z-A that they introduced is some new time pressure. The day/night cycle now is more than just "some Pokemon only appear at night" - nighttime is when you do most trainer battles. Trainers are no longer static NPCs but instead dotted randomly around an arena every night.
Each night, you are forced to run in a circle around an arena trying to battle folks. You can ambush them and generally one-shot their Pokemon before they even attack. They can also ambush you, in a system that frequently feels arbitrary and unfair as I get "ambushed" by trainers that I am watching closely and trying to sneak up on.
Generally, running in a circle repeatedly gets pretty boring. You're also on a time limit; after a certain amount of time the night is over and you get a final score. If you didn't get enough points, you need to go sit on a bench to trigger another night cycle and attempt it again.
The day/night transition is also somewhat buggy. It seems to be used to mask a reset of the world in some way. This means you can be mid-battle with a wild Pokemon and suddenly it gets reset out of nowhere after a short cutscene. Very annoying.
Most annoying of all is the lack of any options in the options menu. Every Pokemon game has gotten worse about their options menus. When fighting, you have to hold LT to select your target to fight. You basically have to keep LT held down at all times in any combat scenario, with a few exceptions. There are no accessibility options, nor is there any way to make it a toggle (which Arceus had!). This makes my left index finger very, very sad. I don't know why Game Freak didn't even consider that people may not want to hold the trigger down for hours. Similar functions like auto-sprint are also missing.
The tutorial is also excessively long, exceeding the level of annoying that Sun and Moon's tutorial had. There's a big city to explore and it takes more than an hour for the invisible walls and main story nags to go away! And then you aren't given access to a core movement ability until you're halfway through the game! (Which, granted, isn't ENTIRELY out of line with the tradition of Pokemon games, but I wasn't expecting to get a new piece of kit so late and spent far too long trying to access places without realizing that the game was purposely stopping me from doing so.)
Despite all this, there's still a lot the tutorial fails to teach. They tell you to clear rocks with Rock Smash, but not how to clear purple ooze (use any water-type move). You'd think if they're going to hold your hand anyway, they'd at least explain everything you are expected to know.
Pokemon fans are in the same boat as Sonic fans where most games in the franchise aren't very good so you sort of have to grade them relative to each other. But I refuse to grade on a curve.
As a Pokemon game, it is decent. Better than some of the other outings. But it tries to be a real-time combat action game and doesn't do a great job.
If you're a PokeFan, buy it! You'll have a good time. But if you're just a casual gamer, you can have a better time with an emulator and a copy of Pokemon SoulSilver or Pokemon Platinum.