I recently purchased and installed the Maelstrom 2.8.15 edition after playing 2.8.0 extensively.  The biggest difference between the two, at least for the purpose of this discussion, is the addition of the Gamma, Contrast, and Brightness sliders in the Options page.  Overall, the game graphics seem darker than the standalone 2.8.0 version, and unfortunately, the subject settings are greyed out so they cannot be changed to brighten the scenes.

I've adjusted the values in the options text files (both general and character save folders) without much difference in performance, and I've come to conclude these must not yet be fully implemented.  However, the game is still dark.

Is there any way to adjust the environmental lighting back to previous editions, or fix the greyed out setting sliders, in the latest edition?  It would be a shame to have to ignore all the changes since 2.8.0 just because of an apparent environmental lighting issue.

Having written the above, I decided to go back into the config settings and try one more time.  I realized I did not have the "full screen" option checked.  Once I did that, the options became available and all is good.

Just thought I'd leave this here in case anyone else has similar issue.

Yes, unfortunately, for DX8 and DX9, gamma settings using SetGammaRamp, which is the DirectX function those options are sent to, are typically unsupported unless full screen. 

See here:  https://docs.microsoft.com/en-us/windows/win32/api/d3d9/nf-d3d9-idirect3ddevice9-setgammaramp

Now I do run in WINDOW mode and the screens are not dark anymore at all. 

It is not compulsory to run in "fullscreen" mode just to have the night

I have reverse my changes above for location and only havee done the below:
It seems that the DirectX engine look at the graphics card settings primarily.

I do got enough lighting for both window and fullscreen mode:
full_screen = 0 (In Options file - window mode)

HD Graphics Card settings changed to:

==============================

Brightness 48 / 100
Contrast   50 / 100
Hue        360 /360
Saturation 14 / 100

For window mode set the resolution X and Y smaller than your actual display X and Y settings.

start.ini file in \Programs" folder
screen_x = 1280
screen_y = 1024

The settings in "options" file in "\Programs" folder for brightness, contrast, gamma only do apply the settings in the game when in fullscreen mode:
"options" file in \Programs" folder
video.contrast=1.0000000 (middle)
video.gamma=1.0000000 (middle)
video.brightness=0.0000000 (middle)

Some update after playing around with graphics card settings:
HD Graphics Card settings changed "HUE" to zero better outlines.

Brightness 48 / 100
Contrast 50 / 100
Hue 0 /360
Saturation 14 / 100

Bear in mind I do play not the original COAS but with mod GOF 2.5.


Some update after playing around with graphics card settings:
HD Graphics Card settings changed "HUE" to zero better outlines.

Brightness 48 / 100
Contrast 50 / 100
Hue 0 /360
Saturation 14 / 100

As I want to stress: Running window mode and get enough LIGHT is possible for night scenes.

Now you can press ALT-TAB switch out of game temporarily to email ect...

full_screen = 0 (In Options file - window mode)