This spoiler free guide will showcase the hidden route to find the moon berry.
How to Find Moon Berry through the Hidden Route
The path, unfortunately, begins at the very end of the entire chapter.
After destroying the power box, rather than jumping towards the bird you must dash to the left, reaching a newly accessible platform.
You have to be very careful. You will need to perform wave dashes and wall bounces on very small platforms.
Luckily though, there is a checkpoint on the way to the moon berry, as seen below.
You’ll reach an opening in the ceiling, where you will have to intentionally die to continue into the moon berry room. Good luck!