This game does something no Sonic game has done for me since Unleashed. I see this game and I see love, I see life, I see passion!
On the surface, it’s like Sonic Generations but with Shadow. A story that serves as an excuse to go back to old levels in Shadow’s history, to see old faces and collect little fan-service pieces that celebrate all things Shadow the Hedgehog… and it fucking works SO well. It doesn’t just work, it FUCKS.

What I expected with this game was a Sonic Generations level pack themed around Sonic Adventure 2, Sonic Heroes, Shadow the Hedgehog, and Sonic ‘06 where you could play as… well, Shadow.
Instead, it plays a lot more like a polished Sonic Frontiers. Shadow has a less powerful boost, and a turn radius much more suited for moving in directions other than forward, forward and forward, and you have to know which of his abilities to use at which times to move forward. And while I hated Sonic Frontiers for feeling like mindless movement through a basic feeling island with jarring platforms and rails floating purposelessly, the design of both the levels and the overworld feels very well thought out and cohesive (oh yeah, and also good as FUCK). I’ve seen multiple people compare it to Bowser’s Fury, and I think that is pretty accurate. You have a really big zone filled with tiny challenges that also get you to where you need to go, which are the more linear (but still pretty open) main levels.

Some of the overworld challenges are annoying, and it sucks that the chests you find by completing (or breaking) the little platforming sections need one of three types of key found in levels, meaning that you can reach a chest and find out you can’t unlock it yet, but this is only more than a minor annoyance if you want to go for 100%.

Shadow’s story is also much better suited for Generations, a game about looking back, than Sonic’s. To quote KingK’s review:

Also unlike Sonic Generations, there isn’t a single level or level challenge I dislike. They really made stages that take full advantage of Shadow’s strengths and stuck with them without feeling repetitive at all. Maybe its existence as a side game that complements the original Generations left it unburdened of the need to be a Big Fucking Ten Quadrillion Hour Game. Whatever the case may be, I have been replaying the fuck out of these levels since finishing it and I’m still having fun with them. I’m still figuring out the perfect run for all the levels, looking at gameplay, mouth agape in amazement, and trying it all out myself.

Shadow Generations also accomplishes something I haven’t seen a Sonic game do successfully since Unleashed: it’s cool.
It’s hard to explain exactly how but, since Colours, no other game managed to pull off the confidence Shadow Generations has. Frontiers tried, which I respect, and Forces pretended to try (bah, I’m sure the developers tried, but the end result just feels like a half-hearted half-step).

I’m, again, speaking in vague and nebulous terms that refer only to a feeling I have, but it feels like the developers commit to the story: they set it up as a serious and earnest look into Shadow the Hedgehog’s relationship with his past and not only do they commit to the tone and beats without a hint of irony, but also to the aesthetic aspect of it. I never once got the feeling that the story, gameplay scenarios or animations lacked energy like Colours, Forces and even Frontiers to a lesser extent did. And when I say “energy”, I don’t mean “fast-paced” or “extra”, though that helps a lot in a Sonic game. I mean the energy behind it. It feels like every aspect is trying to go as hard as it can.

This is the feeling I am trying to get at. Shadow the Hedgehog has swag. If anyone understands what I’m rambling about and knows how to put it into words, please let me know!

And play the game, too. If you already bought Sonic Generations, wait for it to go on sale (or use alternate methods to get it). I played it on Switch and the port was really good! It ran at 30fps at a lower resolution, but it never got muddy, it never froze, it didn't have any input lag and it controlled just as well.