Hey I just tried it in 640x400 software mode and there it works fluently even on the Matrox G400. Then I set the resolution to 320x200 (like in the original DOS Hexen) and it was a kinda strange feeling <!-- s;) --><img src="{SMILIES_PATH}/icon_wink.gif" alt=";)" title="Wink" /><!-- s;) -->, and the great thing is that all the engine features still work - not only are the roofs still in place, but also windows are still translucent. Cool. <!-- s:) --><img src="{SMILIES_PATH}/icon_smile.gif" alt=":)" title="Smile" /><!-- s:) -->
BTW Janis, in software mode when there are large open areas the sky screws up. I'm not sure but I think it does this at those points where in 3D accelerated mode it would not render everything but blend in the skybox in the place of far away sectors. Maybe you can look into this.
BTW rendering distance, can it be set in a variable? At a few places where you can see from one end of the town to the other (or nearly), it kicks in and it would be better for this map if the distance would be somewhat greater (i.e. that this effect never kicks in).