In Station Square, at the Sonic Casino, there is a little ramp on connecting the street and sidewalk. (as if you didn't notice)
Go up to the ramp and do the spin+jump ramping thing on the ramp.
There is a blue tunnel up there (where the train goes throough) that you can land on.
In the city level, (forgot the name) if you are Tails, you can even go to Sonic's part with the building!O.o
Go to that little tunnel thing you fall through, with the lights.Since the edges are ramped, you can also do the spin+jump thing there.That little window Sonic goes through (that takes you to the part when you run down the building) Is now a light. Even still you can reach it using the spin+jump trick. (on the edges on the tunnel I mentioned earlier)When you reach the max height, start flying.Head toward the light.
You will go through it, and to the running down the building part.
Fall down and youll get to the city part.If you hit the capsule,you lose. XP
At the city part (Knux's part) on those edges of the buildings (ramped) do the automatic tails whipping thing. If you go up the ramp, you'll fly up into the air!O.o
Also, as Metal Sonic, (you must have him, because he jumps higher and farther) go to the part when you run down. (don't go in the building yet)
Charge light dash. Keep it charged and do the spin + jump + jump trick. Thok, then lightdash for an extra boost. (when you are almost fallen)
And you will make it there. You can't do much there, but it's cool to get to.
EGG CARRIER GLITCH
Where the boats are that take you there, there is a ramp that takes you to the Egg Carrier.
You must be Tails!
Since theres a barrier keeping you from getting off, go up the ramp.Then fly down, but hover over the part to your right. Keep trying, and you'll go down,still alive able to explore!