If you are struggling with the reversed gravity system, here is a way for you to play all reversed levels just like in normal mode, which according to my own experience, will drastically reduce the difficulty of reversed mode
[Prerequisite]: A windows 10 system is needed.
Below are the settings you want to go with:
1. Head to the "Xbox Accessories" app in XBOX One -> Configure controller -> Button mapping -> map "A" to "D pad left", map "B" to "D pad right", Done -> Check "Swap sticks", Done.
2. In Windows 10, right click desktop and select "Display Settings", switch Orientation to "Landscape (flipped)", click "Apply" then "Keep changes".
3. Open the "Xbox" app in windows 10, stream your console to your computer screen.
Now you can start playing reversed mode by looking at your (flipped) windows 10 screen and also flip your controller by holding it upside down. Your left thumb should be put on the right stick, and right thumb should be put on the d-pad.
With such settings, the left/right direction is still correct, d-pad left is for jump, d-pad right is for (whatever that is called), and most importantly, the gravity system is now back to normal
Hopefully this helps you finish this already very short game even faster.