"14 new posts! This gonna be goo ... oh." 

So I don't know what the hell is going on. My start map is as for now divided by 2 sections: a short cave section, and the skill portal room. No matter what I do (and by that I mean changing light torches' light values, deleting some, up to just deleting all of them), the cave will always be flat-litted, but as soon as the skill chamber show its nose WHOOPS strong shadows and sunlight-quality shadows (At first I did add in sunlight2 but I decided to take it out because there wasn't any impact lighting-wise).
Just look (also in those shots light torches in the first section are supposed to be deleted, and worldspawn's light value is set to 170):
http://image.noelshack.com/fichiers/2016/02/1452545720-razenkrauft20160111214603-00.jpg
http://image.noelshack.com/fichiers/2016/02/1452545717-razenkrauft20160111214611-00.jpg
http://image.noelshack.com/fichiers/2016/02/1452545720-razenkrauft20160111214655-00.jpg
http://image.noelshack.com/fichiers/2016/02/1452545718-razenkrauft20160111214744-00.jpg
http://image.noelshack.com/fichiers/2016/02/1452545721-razenkrauft20160111214753-00.jpg
Also, somehow removing the fog key from worldspawn made the skybrushes visible again in DP.
I don't get it. 

are you using for your lights?
It looks like delay 3 lights(no falloff at all) from afar to me.

Use delay 2/5 for best results, also add the -addmin switch to your commandline for tyrlight. 

I tried to delete all lights (and I mean ALL light entities) this time to see what happens and
http://image.noelshack.com/fichiers/2016/02/1452548500-razenkrauft20160111223743-00.jpg
http://image.noelshack.com/fichiers/2016/02/1452548502-razenkrauft20160111223751-00.jpg
http://image.noelshack.com/fichiers/2016/02/1452548502-razenkrauft20160111223800-00.jpg
http://image.noelshack.com/fichiers/2016/02/1452548500-razenkrauft20160111223817-00.jpg

This still happens if I put -addmin in the light command
WHAT THE FUCK 

outdated lit files with the same file name get loaded by the engine anyhow, resulting in things like this.

http://www.quaketastic.com/files/hollow_odds.jpg

Check values on worldspawn in your map that seem conspicous to you. Even a "sunlight_color x x x", or a "light" value.

Delete those too, report back. 

Some engines in some machines don't like 0-255 values for fog, you have to use 0-1 (like 0.2, 0.5, etc) for best compatibility 

 

fog was already set on 0.3. It showed OK on Quakespasm but somehow not in DP.
A light key of 170 was still active in worldspawn, so I deleted it, just like the lit file (which I deleted once when my lighting problem occured, but it changed nothing).
Now though, after compiling (with the -addmin key still in) now everything is flat-litted (which is brigther than the initial value of 1170, so I assume it went back to 300), even the skill chamber.
What now? 

Dont use the worldspawn "light" key. Ever. It is better to start with a totally dark map.

It seems you have problems in doing what i adviced you to.

Are there any surface lights you may have overlooked?

To make this more clear. A map with no lights and a worldspawn "light" set to 0 should be rendered fullbright when loaded in engine.

So, assuming you deleted all lights and that worldspawn key, plus lit file, you should now see a fullbright map in the engine.

Now,as a test, put one torch in, and recompile. Report back. 

It produces light and shadows as usual, and the rest of the map is pitch black. Water is fullbright but I guess this is a quake feature to allow liquid brushes to be recognizable no matter the light values.
Are things good now? 

I set fog to 0.3, but fog color like "64 192 255". Worked in MarkV at home, but gave me a white screen (like overbright fog) at every other machine. I changed it to "0.25 0.75 1" and now it works in all systems. 

this sounds good.

The waterlight issue is being worked on atm, this is standard quake light behaviour.

Glad to help! 

You can "bypass" the "issue" of fullbright water by using an external 24bit texture. 

with DP? Search in this thread for #15623 and try compiling with the tools linked in that post. 

Hello there, I have been recently playing with Quake mapping and have absorbed a lot from these forums. I find myself stumped and would like to ask for assistance from the many experts here!

Following Preach's NM skill detect map hack I am receiving a crash on map load. Now I thought adding "ai_stand" "SUB_Remove" as a key-value pair would solve the issue but it does not.

I am probably missing something but any insight would be appreciated so I can cater Nightmare to my liking! >:)

Thank you!