Overall this isn't a terrible game, but it could have been so much more. Gamefreak said they cut pokemon to make the richest experience possible but they have cut so many other corners too. Warning there may be a few SPOILERS below.
Region: I am from the UK and there were a few bits that made me laugh like cream crackered however the region in general was lacking life and exploration. Some of the towns seemed to be placed basically for a gym battle with nothing else going on. A lot of doorways didn't open. The routes were very linear and there was no sense of exploration. There was no victory road or big cave system which further dulled this. The wild area, although large was very empty. Online other trainers popping and out caused huge frame rate stutter.
Music: some good tunes especially slumbering weald however a lot lacked the magic of other Pokémon games. The gym leader, champion and legendary battle themes were particularly lackluster.
Characters: these were largely forgettable. There was no interesting storyline with any of them, and corners were cut here, for example there is no elite four they just reuse the gym leaders with different Pokémon which is lazy. Animations were also reused from sun and moon.
Pokémon: some new Pokémon were interesting and despite the cut there were enough to make the game feel varied during the campaign. The issue comes with post game and competitive play and that is where a pokemon game's longevity comes.
Story: weak, there was no main evil team or anyone to take down as such, just a few groups which popped up for perhaps 20 minutes each of gameplay and then vanished, like they were just created to provide an opportunity for the legendary Pokémon. There was no buildup and it seemed everything went from 0-100 real quick toward the end of the game. The postgame was extremely uninspired too, a few new characters were thrown in randomly and then a chain of dynanax battles to the legendary, nothing compelling and rather dull. Dragged on for way too long and probably a way to keep you playing as you still don't have the box legend so the experience appears longer. It is a short game, with capturing most things I saw and breeding some Pokémon I was done in under 30 hours.
Other: Dynamax is the new gimmick and although raids are a good way to quickly get good items and strengthen your Mons the intro battle animations take too long and after the 3rd time it's a chore to watch. No way to skip that I can see. Not as deep or adds as much to gameplay as mega evolution. Graphically the game looks fine but there was so much more potential. The models are the same as sun and moon just retextured so it makes me question again why so many Pokémon got cut if that was the reason? Pokémon camp is a bit of a gimmick. The game is also really easy, I understand it's a kid's game but would a hard mode be so difficult to add? It was less hand holdy than sun and moon at least.
I would recommend this game perhaps for children at Christmas but if you're a long term fan you might be disappointed.