Alright, it's time for a testing report.
On the whole the map is very nice. Most of the points I have to make are relatively superficial ones relating to aesthetics. As always, use your own discretion, since what I think looks good may not to be everyone else's tastes and vice versa. There are a few gameplay points to be made as well.
I personally hate this light flat here. I don't think a light should be so two-dimensional, it should at least have some depth, but this flat doesn't really give you that. I also think it looks out of place in a hell environment. I tend to expect to see it (if it must be used at all :P) in a techbase.
TLDR: I think the opening room would look better with a different flat for the light. That also applies to these areas.
A relatively nitpicky point, but these towers seemed a bit too rough, and I think they'd look better if you added just a few more linedefs to them. Not entirely sure about the lights there, either. Again it seems like something you'd see in a techbase. Apart from that, the room was good. Some nice traps here, in particular.
Again I don't like that light flat. But the main problem with this room was that it seemed a little too square. Still a nice room though. Consider just adding some borders to the lower walls or something to break it up a bit.
I have a vague (very vague) idea that this might look a bit better if the wall textures adjacent to the switch were more similar to the outside wall textures, but this is a very small point.
Don't like this as a side texture for the steps because of the way it abruptly cuts off and doesn't align properly with the stair texture.
I think the wall texture here looks out of place. Just a little too repetitive for such a large expanse of wall. You might want to consider adding a little bit of embellishment to the ceiling in this shot too (something I feel you generally did very well in this map), since it looks a bit too flat to my eyes.
This outdoor area looks alright, but I think you could make it more interesting by adding some more textures to it. For example, consider adding some detail to those red 'pillars' and texture them with marble or metal or something. I also feel the buildings are a bit too square in this outdoor area. No complaints about the lava pools and falls, they were excellent.
Strong and not entirely convincing contrast here.
Wondering why there seems to be a sprite stuck inside the bridge?
The green lights above the bookshelves look out of place in an old-fasioned marble library room.
This is too simple by far. Add some more detail to this outdoors area to make the view more impressive. Looking at the map there seems to be plenty of space.
Preferably make the walls higher so you can't see 'outside' the map either.
I think the open space here is a little bare. Try adding some detail to the upper walls/ceiling maybe?
Here you can see the tops of the barrel sprites, somewhat ruining the effect.
Don't really like the ceiling light in this megasphere area, and the curves in the wall look a bit too sharp.
Texturing around the cyb area is possibly too repetitive in places?
An interesting idea, but I don't know think that it fits with the surroundings very well. Too techbasey.
The lighting here is nice, but it looks too rectangular. This is improved when the trap opens up, but some wall borders would help.
If you look very closely here, the ceilings of the sectors with waterfalls look a bit odd. Looks like you could choose a better (smoother) flat for them.
Also a word about the gameplay here. I think there are far too may lost souls here. If you watched my demo you probably saw how long you can end up waiting around at one of the entrances to the cavern for all of the lost souls to reach you. It makes things a little bit tedious. Maybe reduce the number of souls and add a few more cacodemons?
The lighting on these candles seems just a little off.
Using the same texture for the top of the rock bridge and its side doesn't work too well here, in my view, due to all the misalignments you'll invariably end up with.
Another point about the gameplay here. The lost souls seem to be flagged deaf so when you walk into the room you'll gradually wake up several different clusters of them as you wander into view. I'd prefer it if they all came at you at once. It's annoying wandering into a cavern thinking it's all clear only to be mobbed by souls from all sides once you walk a little way along the bridge. Still, maybe that was the intention :P
I don't like the lava on the ceiling. Some people find it emphasises the point that you're in a strange, unearthly place where the ordinary rules of physics don't apply, but I find it a little off-putting in what has been a conventional hell map up until this point. Still, as always, YMMV.
I like the idea, but not the SHAWN. Surely you can find a more suitable floor texture than that?
This illustates a problem that the original Vulcana had as well. The rad suits are too far apart. I didn't check how much damage the lava does, but you could conceivably lose most or all of your health before you get anywhere near a rad suit in the lava. Could be solved by putting one at the top of the lava caverns at the start.
Hard to highlight it, but something about this room looks weird to me. Too much texture variety perhaps?
The secrets I found in my demo (Soulsphere, backpacks and chainsaw, shootable megasphere, plasma gun) and the BFG secret were well positioned, but the rest of them seemed just put in as an afterthought. There weren't many hints as to their existence (I'm not a player who likes to regularly peruse the map) and some of them required shooting the door instead of using it to get in without giving you any indication of this. Most of these 'extra' secrets looked like they might make things too easy as well. Consider removing 3 or 4 of the 9 secrets in the map maybe?
That's all the feedback I have for the moment, there may be more at a later date (or not). Looks like a worthy addition to the project, as I expected :)