TL:DR - Sonic Prime is a great show for fans, kids, and non-fans. It takes its time to introduce us to all characters without needing a prior experience.
Sonic the Hedgehog has a few TV shows, and each has its charm. However, this one is right now the best for me!
The animation is fluid, lovely, lively, wacky, and wholesome on all levels. I've found only a few instances where it maybe looked a bit strange. Basically small nitpicks.
Models for characters or environment are really nice and detailed. Sonic and his friends aren't much different from their game counterparts. But their alternative-selves, that's when the fun begins. Each has a distinct clothes and personality quirks. They are both similar and different from the ones we know.
Voice acting is spot-on. Every person sounds in character, full of emotions and believable. It may only take a while to get used to, but I don't mind.
The weakest spot is the music. There is some background one, but nothing that would be as memorable or catchy like Sonic X or SatAm Sonic intro. Which is a shame, but nothing that would ruin the experience. The theme is also only a few seconds long.
Action scenes are really fun to watch and none felt like recycled assets from the previous ones. The creators had fun with this one, as some has creative "battle moves" and flow. They weren't kidding about the Marvel-Movie-like action sequences :-D Some looks really epic.
The story is simple in its outline, but I feel it's more complex than it shows in the first 8 episodes. And for a kids' show, it has some dark implications and "side-notes". We visit three alternative worlds where the Dystopia works as a hub, and we will cover the most through the whole series for sure. Jungle and Pirate world get 2 episodes each, which is a good length.
There was enough time to get introduced to old-new characters, get the gist of their world, and to get a "complete" mini-story arc with a satisfying pay-off. Each universe had a focus on a different character, but the others got their spotlight too. I don't doubt we will revisit both worlds in the next episodes. But I also hope we will get one or two new ones for the later parts.
While I may be 30+ I find the humor chuckle-worth most of the time. At worst, I smiled. Sonic is a loveable goof, but can be serious when realizing the situations requires it.
Now to characters themselves. Sonic has flaws, visible ones. That makes him a lot different from Game Sonic or Sonic X, where it was more like "kinda a perfect hog changing others" than a real person learning from his mistakes and realizing his short-sight.
Here, Sonic is influencing others, but also learning from the same people. It's a growth on both sides. This is like with Movie Sonic, who is moving from a carefree kid to a more mature and wiser young-teen across two movies.
The other Prime character is Shadow. He is more mature and like an older-brother to Sonic in this version. This is visible in his first fight with Sonic, when he is visibly less aggressive and tries to reason with Sonic. Albeit he still uses force to do so which backfires. Both needs to learn to speak without spin dashing XD I eagerly await his role in the next episodes as he will lend Sonic his hand (once they can stop punching each other XD).
Some people mentioned jumping a bit back and forth to Sonic's memories is confusing if binge-watching. I do not see it that way. I'm glad they did it, as it allows for the pace to change without it feeling sluggish or weird. Not to mention, we get to see POV's of others and how or why they were there meeting with Sonic.
The pixel-art memories are a cute detail.
