You talk about a game that was a console seller, while the speed and flair of the first game certainly caused kids who owned Nintendo's 8-bit grey box to turn some heads, Sonic the Hedgehog 2 likely moved a good couple thousand units. It was also a legitimate answer to the Super Nintendo, which had exploded into living rooms the year before. The bit wars were truly heating up, and the competitors were swinging.

Going back to early 1992, most living rooms are enjoying the vast map of Super Mario World and sticking some of those landings in Pilotwings. Sega was still churning out some quality games, but one day, kids turn the pages in their video game magazines or comic books, only to see the silhoutte of Sonic and a two-tailed fox facing the horizon. The diabolical Dr. Robotnik looming over the giant "2", the hype surrounding this poster had schoolyards buzzing. I was an absolute gamehead by the time I was 10, and I used to draw so much video game artwork, this image was one that I could practically doodle in my sleep. This was no doubt one of the most anticipated games for the platform. 

Sonic 2 feels very similar to the first game, which while it was an exhilarating experience but it was rather flawed as a platformer. Sega ironed out some of the inconsistencies from Sonic 1 and made some good changes to better accommodate the blend of speed and exploration the game calls for, so overall, the navigation feels more thought out. 

Some of those changes include level structure. Sonic's wonky physics remain, so the developers kinda did a better job of striking a balance with how Sonic interacts with the environment, like having stages that don't harbor as many inclines and better placed bounce pads. Sonic's new move, the Spin Dash, helps give him some immediate momentum. Ironically, despite being a speedster, Sonic's initial step has always been sluggish.

This has been a growing belief of mine with the Sonic franchise, the layout never really complimented the character. You WANT to go fast, but more often than not, it proves to be a hindrance. It's something that would be a hurdle the franchise could never consistently clear. That being said, Sonic 2 control-wise is significantly less stressful than its predecessor.

The addition of Tails pretty much adds an extra attack for Sonic during solo play. Since he's invincible, poor Miles Prower just gets knocked around by the stage hazards, if he's not getting left in the dust completely. Players can select between Sonic and Tails, and they play pretty similar, for the most part. It can also be a multiplayer game, so hand that controller to the youngest sibling and go for it. 

This is also the introduction to the "Super Sonic" ability, a transformation Sonic can activate once he's acquired all 7 Chaos Emeralds and holds more than 50 rings. As cool as it appears to be, and adds some things to the lore, I hate this in-game. Sonic moves nearly three times as fast, and is even more uncontrollable. On top of that, it drains rings by the second. Yeah, you might be practically invincible, but it's easier to tightrope across the Grand Canyon on a slack covered in Crisco than it is to steer Sonic in the right direction.

Speaking of getting the Chaos Emeralds, which is the only way to get the complete ending, Yuji Naka and co. decided that the nauseating spin cycle that was the last game's bonus stage was really stupid. They were omitted for the slightly more preferable half-pipe course where it's a race to acquire as many rings as indicated, lest you fail. This still isn't really all that fun to do, but at the very least, Sega was thinking something a little more intuitive. Accessing them is less of a pain in the ass, as now you just need 50 rings at the checkpoint in order to be transported. Considering how often you may run past the giant portal power ring at the goal in Sonic 1, yeah, much more preferable. The half-pipe stage does show off some of the texture work and sprite modeling the Sega Genesis was capable of. As the years passed, the graphical prowess of the 'Drive was being realized. 

With great music and better designed stages, and less of an attempt to throw him in water, Sonic the Hedgehog 2 is a much more improved game. With his new sidekick and some new moves, this helped propel Sonic as a character and a franchise even higher. The Sonic games still don't really hold up well as ideal platform games the same way the Mario games do, but the blinding fast gameplay does have its appeal, it just takes some readjusting.