This game is a celebration of the hedgehog's 20 year run thus far. It's broken up into three eras, each of which features three stages, a rival match, a boss fight, and several optional challenges. Playing as either classic or modern Sonic, you play through various stages from all of the major titles in the series. The first era is the classic era, featuring stages from the original Genesis games. Then you move onto the Dreamcast era, featuring levels from the Adventure titles, as well as Sonic Heroes. And the last era is from the current generation, featuring stages from the 2006 Sonic the Hedgehog, Sonic Unleashed, and Sonic Colors.
I didn't realize that they were only going to include a single stage from each game, and I was initially disappointed to see them go with some of my least favorite levels to represent the classic games. Now, I know what they were going for with this level set-up, but since the modern style of Sonic has spanned over the previous two eras, the classic Sonics do feel a bit under-represented in comparison. I especially question them using levels from games as current as Sonic Colors, which just came out only a year ago (not to mention the Colors level is by far the worst, and relies far too heavily on stupid gimmicks).
But this is one of those games where it really is easy to get bogged down talking about what should or shouldn't have been included, when really, for the most part, what made it into the game is actually quite fine as it is. And even though several iconic stages didn't make the cut, the game does a good enough job throwing in little references and tributes to anything not included, such as the spinning top from Marble Garden being used in Sky Sanctuary, or the Hydrocity-esque section in Seaside Hill.
As far as the gameplay is concerned, every stage is broken up into two acts, one for the classic Sonic, played in the original 2D style, and the modern Sonic, played mostly on a 3D plane with occasional 2D sections, and using the Unleashed control scheme. The classic gameplay isn't exactly how you might remember it. Sonic doesn't continue to gain momentum when you roll into a ball while in motion, and you're forced to mash the spindash button multiple times to actually launch him off, where as pressing it once won't do a damn thing. These are minor issues, but noticeable for any seasoned Sonic vet such as myself, and they're the kinda thing that takes a little getting used to. Controls aside, if there's one complaint I have about the classic levels, it's the fact that the 3D rendering in them makes certain traps hard to distinguish from the rest of the environment. Spikes are especially hard to decipher, where as in their original sprite forms, the spike traps always stood out.
The original classic stages are all well and good, but what's really impressive is the re-imagined modern stages in the classic style. Crisis City feels very reminiscent to Lava Reef Zone, and City Escape may be the most imaginative level they've come up with in years. I also love how, in many cases, they took the overly generic baddies in the modern games and managed to give them a classic style personality.
The classic stages impressed, though that wasn't much of a surprise. The big shocker here was just how good they nailed down the modern levels. Modern Sonic is actually oftentimes even more fun to play than his classic counterpart. It's just so fun zooming forward and zipping from enemy to enemy in midair. They finally got 3D Sonic working, and working well. There's little to no cheap deaths, where as prior 3D Sonics were riddled with poor controls, buggy sections, and bottomless pits that kept killing you over and over. Nope, this game's smooth sailing for the most part. And Rooftop Run is pretty much just absolute pure gaming bliss, possibly even topping the original City Escape from Sonic Adventure 2 as the best stage in a 3D Sonic game.
The other portions of the game are the rival matches and boss fights. You'll face off against Metal Sonic, Shadow the Hedgehog, and Silver the Hedgehog in what are essentially boss fights on the go. They're easy enough, though the Shadow match was a pain in the ass just figuring out what exactly you were supposed to do, a problem that would later resurface with the final boss. Each era also has an actual boss fight, with you taking on the Death Egg Robot (a ridiculously easy version of the notoriously impossible Sonic 2 boss), Perfect Chaos, and the Egg Dragoon. Most of these fights are pretty straight forward, and you'll receive a chaos emerald for successfully completing them.
Then after all that's done, you move on to the final boss, the Time Eater. This fight features the classic Eggman (nobody calls him Robotnik anymore!) and the modern Eggman taking on both classic and modern Sonic at the same time. The Sonics are in their super forms, in what is essentially a throwback to the Doomsday Zone fight at the end of Sonic 3 & Knuckles, minus the fun. This is probably the most obnoxious boss fight in all of Sonic history. Throughout the fight, Sonic's friends are cheering him on and offering all sorts of useless advice that'll only get you killed if you bother to follow it. This fight is so frustrating, and it all stems from the fact that you really can't even tell what it is exactly you're supposed to do. I actually had to look up online just how to beat this guy. It was easy enough once I knew how, but jeez, I woulda never figured that out on my own, and several other people online expressed similar problems with this fight. This may be the most disappointing conclusion to a Sonic game yet.
But all in all, good as the game can be, the real hero here is the music. My god, the music is tremendous! The Sonic series has always been known to have good music, but this is seriously some of the best stuff to come out of this series, or any video game for that matter. The modern remixes of classic songs are just a joy to listen to, but even more so than that is the classic remixes to modern tunes. The classic mixes for Crisis City and City Escape especially blew my mind away. And when you're in the mini hub section between stages, a softer, more symphonic version of each stage's song will play. I've spent so much time with this game just keeping Sonic still and listening to these songs in this area, they're just so, so good.
So yeah, overall, despite a few shortcomings, the game is good, even if it is relatively short. But there's tons of replay value to be had, and lots of stuff to keep you busy after you're done. It's particularly nice to see that they've learned from the mistakes they made with Sonic and the Secret Rings by making the challenges optional this time around. In fact, all of the major flaws that have ruined past Sonics are absent from this title. There's no forced side missions, no big, boring hub worlds, no game breaking glitches, no werehogs, and for the most part, no stupid, pointless gimmicks. This is straight up Sonic the Hedgehog, brought into the modern age of gaming the way he should have been 10 years ago. It's taken them a long while, but Sonic's finally up to the quality we'd been hoping to get for years. Welcome back, Sonic, and Happy 20th Anniversary!