Beached!: Jump through the barrels to the right of the ship When you're in the forest place stick to your left and take the small bridge

Bridged: Stick to your right and go through the small grass area with the traffic cones After you go under the second Bonboon waterfall stick to your right and there will be a gate that will open but make sure that an opponent is ahead of you or else you'll have to wait for it After you take the huge leap stick to your left and take the small area with the barrels

Civilized: When you hit the first boost-panel you just wanna keep going forward When you hit the second boost-panel you again just wanna keep going forward After you've took the second shortcut there will be 2 paths, but it's faster to go down other than the other way around.

Garden: There aren't really shortcuts in Garden but you can cut some corners where the yellow & purple platform thingys are

Frosty!: Once you get out of the first tunnel stick to your left and there will be 2 leaps When you enter the second tunnel once you see the fourth candy cane you wanna turn right After crossing some bridges and going through some tunnels you wanna stick to your right and there will be a leap

Cha-Cha-Changes: There aren't really shortcuts in Cha-Cha-Changes but once you get out of the tube with the water you can take the conveyor belts upwards

Factory: Once you make it out of the place with the conveyor belts you wanna just wanna keep going forward After you make it out of the small tunnel you wanna take a turn to the right and there will be a leap

Here's a video with the shortcuts: