As mentioned, Sonic Teams greatest challenge was maintaining a sense of speed for the series while finding controls that made sense. The result is now that, by default, Sonic doesnt burst off with a tilt of the analog stick. He walks until you use one of the GamePads triggers to engage his running speed. This too is actually not full speed. Holding down the second trigger will pull Sonic into a ball, giving him access to his full momentum, which Iizuka likened to the Boost speed from previous titles. By creating a tiered structure to movement, Sonic Team is hoping players will be able to navigate the wide range of level designs, exploring and running as necessary.
Thats also where the Parkour system comes into play. In previous 3D Sonic games, even if you're running through a level at top speed, if you hit an obstacle you stop instantly, Iizuka explained. To avoid this, we added a new action to keep Sonic running, even when you hit an obstacle. To make sure it only happens when you want it to, it's triggered by the player holding the run button. Like any game, automating actions brings a certain risk, but doing nothing means Sonic games continue to run into a brick wall literally in the case of gameplay.
