Its good and bad
Good
Most ambitious main series Pokemon game since Black/White
Nice big world that encourages exploring
being able to traverse anywhere once you upgrade your legendary pokemon
Nice story with Arven/his pokemon, and his dad.
Likable gym leaders with personality
Non linear. there is a path you should follow but there's 3 main campaigns you can mix and match and tackle in whatever order you want
Some cool new pokemon designs, I like the paradox pokemon especially
Nice areas to look at while grinding such as the Zero area.
finally have a controllable rotating camera in battle.
they cut out a lot of the grindy bullshyt, especially with relearning old moves
soundtrack is wavy, this is something pokemons always excelled at and its no different here.
Drop in co op. finally explore the world in full with a friend(not restricted like previous co op in pokemon)
Bad
Less character item customization than previous games
No proper scaling so while u can tackle whatever you want, u can end up OP if u hit harder stuff early
Technical issues. pop in, frame rate shyts the bed, characters glitching into weird animations(was battling an Iron Treads today and it kept turning big and small during the battle. gave me a jump scare when it started. aint crashed but have read others have. this is the games largest sin.
Graphics. while there are some nice designs to characters and environments, this aint all that graphically, which makes the technical issues more frustrating.
Cities feel small. to add to the smallness, many of the buildings cant be entered.
while the main cast is great, many of the regular NPC's aren't interesting like previous games. lack personality.
Needs a better post game. something beyond filling the dex and re-battling gym leaders.