Nice map.
But rather low on ammo and health near the end. After axing the Shambler I had to do 2 Demons by hand as well.
On Nightmare (of course ...)

Played on skill 2. All killed and 2 out of 3 secrets found.

Around the same level in brushwork as Id maps with some details, mostly 2D linear branching layout, typical sadlark progression toned down, good lighting, many ambushes and short-middle range combats, around the same as Id maps in difficulty or higher, tight on ammo, way lower than iD maps on health and armour, decent secrets.

It is a solid map with no big issues, save some enemies that can't reach the player and two stuck into the walls. There is some traps that range from too easy and obvious to avoid to mostly unavoidable insta-death on the first run. The ammo shortage on skill 2 and 3 can be overcome by leading enemies on lava and traps or telefrag them which is easy in this map.

The zombie in the key room stuck in its own sarcophagus, making it impossible to kill him and, therefore, leave the room. Deleted.

Some good mapping craftmanship here.