Name of Doom Wad?

Some years ago I had a wad file I downloaded and I wish to download it
again. But..... I have forgotten the name :-( Maybe someone will
recognise it from my description.

The player start is in a wide canyon which is split down the middle by a
river of lava. Quite some distance across the river is a castle.Various
creatures are shooting fireballs at you from the turrets. These are easily
avoidable because of the distance.

You need to go up your side of the canyon where there is a cave system to
the left. At the bottom is a switch which you activate. When you get back up
you find that a column has appeared by the cave entrance with another switch
on it. You also find that a secret door has opened back where you started
and that many flaming skulls have emerged and are coming down your side of
the canyon to stop you activating the new switch. Once they are dead the
switch, when activated, brings up a bridge where you can cross to the
castle.

I dont remember much more but the when you get thru the castle entrance it
is green marble motif and you are greeted by several skeletons and imps. The
first room is large (to scale, maybe 40 - 50 meters).

Name of wad or wad collection anyone????

 

Thus spake stumped:

Try asking in a relevant newsgroup alt.games.doom f'instance