The story and writing is fun even if I'm sure I have terminal brainworms for laughing at some of the meta and fourthwall breaking humor in the game. I think my biggest complain is how simplistic the overall gameplay is. The monsters are just pile of stats, and unlike in Pokemon, there's no interesting abilities, items, or moves to differentiate the monsters from each other outside of there stats. It leads to you just wanting to use whichever monster has the highest rarity and hence, the highest base stats. Status effect moves are mostly useless with chances for them being so unreasonably low it's hard to justify remotely using them over moves that just do damage.
The game is definitely more challenging than the average pokemon game, trainers will frequently have full teams of monsters and will sometimes make you fight multiple trainers in a row. There's some sort of level scaling to keep things a decent challenge throughout, though I personally ended up being like 10 or so levels below every trainer in the endgame which led to me spamming the fuck out of healing items to get by. Overall though, I had fun. It's paced well, the story is surprisingly engaging, and the gameplay, while simplistic, is fun off to get you through the whole game.