Nohra's Concealment will be a Half-Life singleplayer modification. It will feature new characters, a lot of custom content and will be story-driven predominantly.
This image shows an unfinished concept of a inclined elevator tunnel which was used in Half-Life several times. The perspective may confuse but it's a 45 degree angle.
Ooooooh Perdy. :o
Hinab, hinab, in's finstere Grab...
oh, errr... nice atmosphere here.