Any2-2

Optimal

Clippa's Nook.

Buffer a groundpound at the start of the level and dropdash up to the intended shortcut to the midway point. You can switch to Marbles at any time.

When approaching the wall, piggyback after rolling off the ledge, then use your clip button to wall clip out of bounds.

You can use your setup button to set up the clip back inbounds.

Using this strat, any 19 is good.

Marbles End

Instead of swapping to Marbles out of bounds, you can instead piggyback jump over the water and keep Checkers in front. This allows you to swap back to Marbles as you go back inbounds and have Marbles in front for the next level. Counterintuitively, this strat is actually about half a second slower, but the time is saved back in the next stage since you need Marbles for 2-3.

Be careful when clipping back inbounds. If you have a tiny amount of space between the wall when initiating the clip you can stand on the ledge, but this won't happen if you touch the wall then use your setup button. If you throw the shell immediately you will fall and usually take damage on the pip cannon below. The safe way to get through here is to buffer a jump and throw the shell after jumping. You may roll through the shell, roll through the barrels, or go over the barrels and spin-dash.

Both strats are nearly identical in terms of time, it really comes down to your detailed execution. Choose the one you're most comfortable with.

Using this strat, a low 20 is good.