I would have greatly preferred to have reviewed this and "Sonic & Knuckles" as "Sonic 3 & Knuckles" (as one game) instead of doing them separately, but I guess it's nobody's fault except the limitations of the otherwise awesome Sega Genesis. With that said, I'll do my best in reviewing them both concisely. Anyway, after the monumental heights Sonic 2, it was a bit tricky to determine how to bring the blue blur to even higher heights. Sonic 2 already balanced the great level design and speed, as well as did everything else wonderfully. What could be done? Well, it appears that the answer was to just go nuts and go all out. Make the game as big as can be and make it unforgettable.
And, if you ask me, they not only did it, but also made, if you ask me, the absolute best game(s) on the console, period. The visuals are a lot more varied and full of life than ever before, the music is some of the most diverse and jam packed in a Sonic game ever, the levels are, in my opinion, some of the best ever designed in a Sonic game, the boss battles are inspired and fun to take down, and the blue sphere special stages are easily the best in a Sonic game to date.
While the half pipe special stages in Sonic 2 were fun in their own right, I really wasn't a fan of how big the difficulty spike was. I thought it made the game feel a bit too unbalanced (especially at the end), making for some slightly artificial difficulty, which I cover more about it in my Sonic 2 review. Shameless plug aside, none of these complaints apply here, as the blue sphere special stages have a near perfect difficulty curve. That's not to say they don't get really hard (they most definitely do by the end), but not one of them felt like they were asking too much of the player at once, and the way each blue sphere level is designed is not only fun, but also gradually more challenging with each stage, and is incredibly satisfying to fully grasp and complete-something that I can't quite say about any of the special stages in past games.
Speaking of which, how do you access these ones? Well, instead of hoping you have enough rings at a checkpoint (which still grants you access to mini games for power ups and rings in this game(s)) you find secret areas in each level where you can access the special stages. This brings me to level design. In my eyes, this game(s) has the best levels in any Sonic game to date. Because not only does it focus on speed, but it also incorporates exploration and thoughtful tropes like the wonderfully executed elemental shields that not only protects the player from one hit, but also gives them an ability based off of that element. They're not only fun, but also fit perfectly with the more natural environment aesthetic this game has, and it's a shame that we'd have to wait until "Sonic Mania" to see them again.
All of this helps each level to work wonderfully, as they're not only big and fun to speed around in, but they're consistently interesting, and if you mix that with the fun special stages that'll hook you to keep trying again, these levels are just excellent all around.
Really, the only "flaw" I can think of is that this game, on its own, feels maybe a touch too small (not by a lot, this would still be an okay length if this were it). Though, because this is all technically one half of a much more grand package, I don't really think it counts nowadays, especially what with how easy it is to play the full thing.
Overall, up until "Sonic Mania", this and "Sonic & Knuckles" together would be the closest to perfection the blue blur has seen yet. Sure, one could argue they'd rather just go super fast and not worry too much about exploration like in Sonic 2, but I feel all of what this game(s) brings and improves upon, this game(s) still reigns supreme as one of the best of all time. Plus, who doesn't like Knuckles, who would become one of the most iconic, memorable, and kickass video game characters of all time?
