Even after 20 years, it's amazing how quickly muscle memory returns. And not just in the hands or the arms; I'm talking in the extraocular muscles—the ones that move your eyeballs. Blasting through that first, long runway that opens good old Green Hill Zone, Sonic the Hedgehog plowed headfirst into a garden-variety badnik. On restart, he did it again. My eyeballs literally were not tracking. I thought for sure this review of Sonic Generations would provide a cruel awakening to the fact a young man's game had passed me by.

After a few runs, though, the tracking returned. I knew where to look on the screen to anticipate the next threat. The camera raises and pans spoke to me again, showing me where to go. Muscle memory returned to my thumbs, tuned to the floaty physics. "Always look for the high road," I recalled. I was playing Sonic the Hedgehog again.

This may be why I was chosen for the review. After college I didn't touch Sonic, drifting to other genres and platforms and thus not becoming one of the many implacable voices in the Sonic nation. I cannot speak to concepts such as the "Sonic Cycle," a self-fulfilling prophecy that usually ends with what was a fun game in its opening acts disintegrating into a letdown.

Detached from that, questions like whether City Escape was really a good choice for a 2D interpretation, or if putting the spin dash on the X/square button is a cop-out, mean little to me. I can sense and admire the obvious fan service permeating Sonic Generations—including its scrupulous adherence to canon and the delightful minimalist main screen evoking the original—but it's not going to get any extra credit.

I'm here to talk mostly about a gameplay legacy that's had an enormous influence on one of video gaming's bread-and-butter genres. My summary appraisal is that the Sonic Generations game experience is very frontloaded: Superb, beautiful, deep platforming challenges in the main stages, with next-to-no reward during boss battles—or in completing them.

Sonic Generations is meant to unite the two distinct gameplay perspectives of Sonic's 20-year history. For those who say the 2D platforming game was better, there is a ton of that in here, and on the whole its levels play more strongly and intuitively. For those who prefer the 3D Sonic, you're getting some of his earlier escapades reimagined and optimized for modern talents like the homing attack.

Canonically, what's happened is that Sonic, past Sonic, and his friends (including the past version of Tails) have all been sucked into a time rupture. It's up to the two Sonics to unfreeze nine worlds, all based on those from past versions of the games. Doing so unsticks their friends.

Was City Escape the best choice for 2D interpretation? Beats me, but it and all of the 2D levels were fun to play in Sonic Generations

After unfreezing a world, you're given a set of challenge levels, which usually involve some goal such as collecting a ring total (or finishing with only one), using a certain skill, or enlisting a friend and employing his or her special talent to negotiate the course. Completing one challenge gives you an unlock key, and three of those take you to a boss battle, which advances the story.

The main stages and the challenge levels (excepting the doppleganger races and a deceptively tough chao-hunting race with Cream the Bunny), are well balanced for playability and challenge. If you're going for speed, there are many spots where you must hit a jump sequence perfectly and then follow it with, say, a perfectly timed series of button presses. But Sonic has always been this way. The physics may be floaty but they're consistent; don't nitpick those. Instead nitpick the placement of the objectives which, to be fair to critics, are on many occasions so far away they turn what looks like an ordinary jump into a very technical one.

There was only one egregious example (in Crisis City) where bad visual information led me to an unfair death. The others may have exploited my fast-twitch impatience (I said "god dammit" repeatedly through this) but they were navigable if I'd taken a split-second longer to assess things. The 3D camera sometimes gets Sonic wedged into the bottom of the screen, with elevated terrain ahead, such that it's tough to see what you're jumping into. Leaps of faith have always been part of the territory, going back to 2D Sonic.

I completed both acts in all nine worlds (it's required) and all the boss and rival fights, but found myself looking forward most to a new territory's Act 1 challenges, playing as the old-school, pudgy, taciturn Sonic. You only have to complete one in each territory to get to the boss; I beat about half of them and still have plenty to satisfy a pick-up-and-play impulse that quickly becomes a just-one-more obsession. There is strong replay value in Sonic Generations, just not in any of its climactic moments.

By far, the boss fights are where the game disappoints the most. Though some will ask for more of them, if they're going to be treated this shabbily then thankfully they are few and far between. You get five rival challenges and three boss stages, followed by a final showdown. What you get in them ranges from frivolously short to teeth-grindingly interminable because of how poorly the game communicates its expectations of you. It will take a lot of trial-and-error, or just heading to Google or GameFAQs when you're ready to huck the controller through a window.

The latter three boss fights are prone to long stretches of wasted action, either in trying to deduce the boss weakness, or in using special attacks or parts of the race course which end up having no utility whatsoever. The final boss battle involves a perspective switch between 3D modern Sonic and 2D original Sonic, and the latter is a bystander in both. I don't consider this a spoiler but a reader service: A charge-up attack where original Sonic can be launched while you're in 3D mode seems to have absolutely no purpose, so don't waste any time with it.

Boss battles and rival showdowns—such as with Metal Sonic—are a big letdown, if not a waste of time.

The game's ambiguous instructions also needlessly make navigating its hub world a chore. Each stage is arranged as a surreal gateway, a main portal to Acts 1 and 2 of of the base stage, with several challenge stages arrayed on a platform around it. You have to jump, ride elevators and hit springs to get to these challenges, there is no fast travel among them, like there is between the standard stages in the character switch menu.

For completionists, it makes it hard to determine how many challenges there are in the first place, much less how many are still incomplete. For those who wish to go back to a specific race, they need to remember exactly where the gateway is on the map, as the icons above it do little to verify it's the one you want. This means a lot of standing in front of the doorway and pressing up to get to the confirmation menu.

These and other little things will do a great job of just driving you nuts. I didn't know you picked up the unlockable music and art by ringing a bell over the gate of a completed challenge. Of course, the game then makes you chase a floating musical note to collect the goodie. Why? Just give me the damn thing. Finally, hiding the Sega Genesis, through which you use the Genesis Controller (purchased at the skills shop) to play an original Sonic the Hedgehog ROM, is just silly. It should be back in Sonic's apartment with the other unlockables.

It may sound petty to call that out, but the process really is aggravating thanks to the constantly trilling music medley, which will drive you and anyone else in the room insane and cannot be deactivated unless you shut off all music or mute the TV.

Given how disposable the story is in Sonic Generations, I was surprised by how much its conclusion stuck with me. Maybe it's because I've been to my 20th high school reunion in this year, and though emotionally I'm still a big teenager in a lot of ways (some good, many bad) I'm coming to terms with being a middle-aged man.

It's not much of a spoiler to tell you that, yes, Sonic triumphs again, and thus there must come a time for the Sonic of the past to return to the past. "Enjoy your future!" the modern hedgehog says to his silent past self. "It's gonna be great!" It was and it wasn't, of course.

Sonic Generations is a strong, sometimes sentimental capstone to the franchise's first 20 years. It's at its best when it reminds you how it felt at the beginning, with so much to look forward to.