Underground

Uuhhmmm,maybe too easy to be able to give you 4 stars... thanks for sharing @Robot B

Spoiler: Video walkthrough

https://photos.app.goo.gl/zjj1ja4zYtxJZQ2A9

@delator77 I am aware of that.
Thank you for your comments.

@Lucky Thank you for your registration of the solution.
I'm glad you played my level.

Very nice design. When I saw it, I immediately really wanted to play. The gameplay is easy but interesting and in a classic style - I love it! Thank you.
I enjoyed it.

Since you also love beautiful design and strictness in symmetry. I want to share my experience with you.
For example: let's say you want to have full symmetry, but for gameplay you need to have several openings-windows closed (like in your level). Let's say you don't want to change the gameplay, but really want to have symmetrical openings-windows. There is a way out - a fence!

Spoiler

It blocks the passage and visibility, but leaves an opening-window in the design))).
This is just an example - maybe my advice will come in handy in the future) I sometimes puzzle over this for a very long time.

@Denis Nazin
Wow! Thank you very much. Your hint are really important for me.

I was thinking on a more complicated level with the same principle as elevators. So I will surely use your advice.

I love the way of your designing 'cause mostly when I construct big palaces like that I get so annoyed and I just hate it sometimes, but your level is a nice one with good logic.