I wasn't referring to speeding through every level. Let's say there's a slope that curves and extends up to a ledge, like they have in every 2D Genesis sonic game. If you didn't have enough momentum to get up the slope, you can just activate the boost instead of going back and gaining more speed or using the Spin Dash. Now that I think about it, why did they bother making Sonic's boost move when he has the Spin Dash? That was the entire point of making it in Sonic 2...