A portion of a GameSpot interview with director Matt Kraemer...
GameSpot: Could you speak a little about what you changed from the first Sonic Boom?
Matt Kraemer: One of the biggest changes is the level design. It's a lot more streamlined, it's a lot more made for speed. A lot of the stages that you see here are built for combo-ing. You can literally combo stages from the start all the way to the end. It was something that we didn't have in the first game, it was more maze-like where you had progression where you would get to a dead-end and then you would have to go back and go at a different pace.
And there's no progression blockers in the game. In the original game, you would play a stage, and then you couldn't move forward because you had to collect these badges. We removed those gates so you can freely move forward at your will.
GS: So this is making good on a lot of the stuff you wanted to do with the last one?
MK: Yeah, and that's something we always do, especially me. I read every single comment--I go on all the forums, I go on NeoGAF… but you have to take things with a grain of salt, especially with Sonic. Everyone's going to hate on Sonic and have something to say, but you look at those comments constructively. I take all the information and granularly break it down, and [say], "People really didn't like that feature, or they really wanted this," and those are the things you focus on.
Most times when you finish a game, you don't have much time when the game is completely together to keep playing it and [think about what needs to be improved]. With this game, we had that extra time, and we did a lot of play tests… and we could see people literally play the game as a whole and see where people got stuck and rectify those.