Slowed speed of the elevators. You can now do the lift jump from the lift to the middle level floor. You can't lift jump to the redeemer anymore (I think).
Fixed piping around elevators so that you don't bump your head when lift jumping.
Fixed piping around Damage Amplifier so you don't bump your head.
Expanded blocking volumes around piping near the pit of death so you don't bump your head trying to use the boots from the pick-up spot to the middle level floor.
More use of anti-portals.
Better zoning.
Set cull distances on some meshes and fluid surfaces.
Rotated the lava pit. Don't ask why.
Fixed some lava zones around the lava pit.
Removed some unnecessary subtractive BSP.
Changed some textures around elevators and other areas.
Other items were fixed or changed that I can't remember...