I have already reported a bug that the large screen of my smartphone in the Lush Climate is dark, but the small one is bright. (Here is the bug report: https://rainybugs.veratil.dev/bug/894/)
I am now one floor down and have noticed that this level is even darker. So I now assume that this is intentional (?). Unfortunately, this makes no sense at all. Because it makes absolutely no difference whether you are five meters or a hundred meters underground: it is always completely dark. So the fact that it gradually gets darker the 'deeper' you go into the cave makes no sense.

Apart from that, the filter does not work properly in places. The cave is darkened so much sometimes that you can hardly see anything of the level. Very often fights are so dark that I can hardly see the opponents.
And as if that wasn't bad enough, it also darkens the Battle Planner - or at least the Battle Planner database. It also darkened the Ofadu pack opening screen so much that I could hardly see anything.

The cave and battle screen are so dark that it is very difficult to see where to go or what kind of enemy it is:
https://s20.directupload.net/images/240716/q8qcsphi.jpg
https://s20.directupload.net/images/240716/7w6bsa2c.jpg
https://s20.directupload.net/images/240716/ax6qudpi.jpg

Mezu's model is so dark that it is hard to see against the dark background
https://s20.directupload.net/images/240716/dr9268bz.jpg

The Ofuda UI which is unnecessarily dark:
https://s20.directupload.net/images/240716/x683pxvs.jpg

All of this cannot possibly be intentional. Accordingly, I would be happy if the filter - if it absolutely has to be there - was only displayed where it makes sense, namely in the cave system, not in UIs. And that the filter also works reliably and is not twice or three times as dark in places as it actually is. (I've also had the opposite, where the cave was significantly brighter because the filter probably didn't work at all.)

Although I would generally be in favor of removing the dark filter, as I said, it makes no sense because it is equally dark everywhere as soon as there is no more light.
Or at least make it so that the parts of the cave where you have already turned on the switches no longer have the filter. (And that it remains light afterward when you visit the level again at a later point.)