A lot of Sonic fans value the storytelling and characterization in this series, so I thought I'd pose a challenge. The Plinkett test is based on the legendary RedLetterMedia review of Star Wars: The Phantom Menace, in which a character named Mr. Plinkett (Mike Stoklasa) asks a few people to describe a Star Wars character in a certain way, in order to prove how devoid of substance the prequel trilogy's characters had. And this, I think, can extend to any medium. So, to paraphrase: So, for Han Solo, you got these kinds of responses: Essentially, you must describe a character without mentioning their: Appearance Skills Plot relevance Relationships You must only describe the character in terms of their personality. The idea is that the more descriptive you can get, the stronger the character is. And for the Sonic series specifically, I would suggest only using the canon video game universe, otherwise it'd be confusing. I asked a couple of Sonic communities this question for Amy Rose, and I got some decent responses, but they ride the line on mentioning plot relevance and relationships: Others were very basic with hardly anything of value to say: Someone also said that Sonic as a series simply isn't sophisticated enough to pass this test, because it's low-caliber media, so no character can pass it really. But if that's how people feel, then I have to wonder why it matters in the first place whether someone like Shadow is flanderized or not.
I find these analyses interesting but I don't think all characters need to be very deep. Take Persona 4. I love that game, despite how incredibly flawed it is, but the characters are very straightforward and can be summed up fairly quickly. Yosuke is insecure but loyal and subtly introspective. Yukiko is formal and genteel but also has a weird side to her and can be unexpectedly fiery. Etc. What makes the cast great is how they interact with one another rather than the complexity of the individual characters. I think Sonic is similar. The cast can be summed up fairly quickly. Sonic is cocky but genuinely cares about his friends and has a strong feeling of justice. He loves freedom and independence but shares connection with his friends. Tails is smart and undyingly loyal but is occasionally insecure and feels he needs more independence. Knuckles is naive and sonewhat dumb but he's guided by a strong principle of right and wrong Etc. But in the best Sonic games it's the way these relationships clash which is appealing. In Adventure when Tails gets his independence, its partially because Sonic has blasted off somewhere on his own because that's the way he lives. In Sonic 3 and other games/media, Knuckles' turn to the heroes' side is engaging because he shares the same sense of justice as Sonic when he finally realises he's being tricked and instinctively acts like him.
Feel like a lot of the major/recurring Sonic characters could pass this test easily, especially if you dip into the comics or the movies or whatever else where they’re more fleshed out. Like I think all the major movie characters are pretty well-defined.
I suppose if we were to use Shadow as an example: Prior to the "meta era" he's a focused, pragmatic character who despite having a strong sense of justice could and would believe the ends justify the means if pushed to it. During the meta era he's a brooding, arrogant character. I struggle to go much further than that without mentioning relationships or plot.
This character is defined by their sense of duty. Having isolated themselves due to the expectation of that duty for most of their life, they struggle to place their trust in others, remaining aloof and prickly to those around them. However, after a particular adventure, they learn to open up to the world and rely on others when the task is just too great to accomplish alone. Although they have retained their refined and serious exterior, the turmoil of their isolation has now been replaced by a fierce passion to protect and help their friends. I’ll let y’all figure this one out, it’s pretty obvious but I think a testament to the strength of this character.