Here are the changes:
- refactored the blocking volumes at map edges. They are still pretty clumsy and can be improved a lot, but at least now they don't make you think about suicide or homicide;
- removed all physics/leaving battlefield volumes from roofs. I hope to make some improvements about roofs, but using not-working 0.5 dmg/sec with Leaving Battlefield message is not the best way to prevent roof camping;
- removed some unused volumes which serve no apparent need;
- anti-portals in buildings seem to be OK, I can't think of better shapes (actually I can, but I greatly doubt that wasting another day or two to make them perfect will give any visible effect on FPS)
- removed stray health and link ammo pickups, they are to be replaced with Kegs and CustomWeaponLockers later;
- removed Hammerheads, they are to be replaced with Cicadas. I still do not want to add too many fliers, but maybe one or two on other nodes will do.
Thanks to Cat for RGB8 render suggestion, it transformed 45MB -> 35MB

Still searching for a way to replace projector material from script.
A question to modders: is there a reason to have two big walls and a piece of land under the BSP or is it just garbage?
Also, one more question about textures: there is texture on buildings, part of which shows windows as fake "mirrors", but the reflexted texture is daylight one. How can I edit it to reflect correct map state or make a replacement?