The show follows who else but Sonic who was Isekai'd to the human world where he meets Chris Thorndyke, a mostly boring kid who's only personality trait is simping for him. After he reunites with his friends they must collect the 7 Chaos Emeralds before Eggman does, or atleast that's what the show implies because in most episodes absolutely nothing happens, the story has incredibly low stakes because everyone ends up accepting Sonic into society less than a third in, the main characters besides Knuckles don't care about returning to their planet, there's not even a reason for them to return until 50 episodes in, and said reason is a confusing one. Eggman and his goons are as incompetent as Team Rocket, except that doesn't work here because Team Rocket is just a bump on Ash's road to become a Pokemon Master, not the main concern.
This leads into a bigger problem I have with this show and is that almost every established character has been flanderized and all the new ones (With exceptions) are one-note, for starters, this is were "Fangirl Amy" and "Idiot Knuckles" pretty much came from, Sonic himself does absolutely nothing a lot of the time besides sleeping, and he himself acts like an Idiot a lot of the time and then there's Chris Thorndyke, he's supposed to be relatable but lives in a huge ass mansion with two famous parents, a scientist grandfather and two racial stereotype butlers. His conflict comes from being alone and supposedly having no friends, except he already does, and one of them is far more sympathetic and interesting than him yet has a single episode of development, but none of this would be so bad if he didn't do something so selfish you instantly grow to hate him at the very end of Season 2
Seasons 1 & 2: 4/10 - The only redeeming factor is that it genuinely made me laugh sometimes.
The show however is redeemed in it's third season originally made as filler comissioned by 4Kids, as it tells the story of how an alien race called "The Metarex" Invades Mobius (I'm refusing to call it "Sonic's World") and how Sonic and friends must travel trough space to gather the 7 Chaos Emeralds that Sonic scattered. The genre shifts into a space opera heavily influenced by Leiji Matsumoto's works and it's full of moments that wouldn't be too out of place in one of the Sonic Adventure games. This part carries the show and is a must watch for any Sonic fan, I just recommend skipping 2 seasons of lame stuff to enjoy it.
Season 3: 7/10 - Tbh I haven't seen Yamato yet but this kinda makes me want to.
