Just filling the obvious gap. As someone who loves Sonic 2 and considers it the best of the classics, followed closely by Sonic 1, here goes... The zone progression is kind of weird. It doesn't build a strong narrative through-line. I think the difficulty curve is good though. Some of the water-filled bottom paths in Aquatic Ruin Zone are a bit too punishing IMO. Since they made it fairly easy to avoid the water entirely, it seems they took a different approach to the lower route than Labyrinth Zone. I just think the level design in those spots could be better, so the player doesn't feel totally screwed when they fall down. Otherwise it's a great zone, and not every underwater area is bad. In Oil Ocean Zone, there is one instance where the seahorses fire at you from just off screen, making it difficult to avoid without knowing when it's coming. Grievances with Metropolis Zone: The crabs have a messed up hitbox and it's a tad annoying. There are three instances where a slicer is placed badly. One in a fairly enclosed area, where avoiding his attack is made extremely difficult, especially since there's just enough empty running space to be full speed by the time you reach him. Another that walks inside the entrance to one of the transportation tubes, so he's hardly visible and you'll just run into him without realizing he was there. Finally, the guy who looms overhead when you go up a particular vertical spring gimmick. You have to get hit by him and be launched up to the opposite ledge to continue on that route. You can avoid this one by taking the opposite route through the stage, but he resides in the more obvious direction. Other than those, I absolutely love Metropolis Zone as a whole. Three acts and all. Slicers, under most circumstances, can be easily dealt with by jumping over their attack, and the starfish attacks can be avoided as well. Having to run backwards to reset the screw lift if you get knocked off is annoying, but I don't consider it that big of an issue honestly. The bad ending is better than the good ending. You can't fly as Tails.