Thanks for the great feedback!
The sound in the jumps was at the very beginning and when the elevator was turned on. Maybe a mistake?
After the deadline, I redid the sound of the jump and added sound to the intro.
Also now a ray can notice a character when he is standing on a box.
Yes, when a character drags a barrel, then enemies can see you. It is enough to lower the barrel to the ground.
Cntr + D - this is really very funny :D I completely forgot about this hotkey!
You can also use the gamepad, if convenient.
Thank! To be continued ;)