korell: Hmm, double check on that gamma setting in the nGlide configurator. I've had a look and it goes from 0.5 to 1.5. However, that is the latest version, 1.02, but I can't see why that would be different for an earlier version.
The setting is stored in the registry at the following location:
HKEY_CURRENT_USER\Software\Zeus Software\nGlide\Gamma
The value goes from 0 to 10, corresponding to the settings for 0.5 to 1.5.
Hey, thanks for the extra info... glad to know where the value is stored! GOG shipped the "nglide 0.99 configurator" with my SiN Gold, and the Gamma setting is a pulldown that goes from 0.8 to 1.2. But I'll try the 1.5 in the reg and see if that takes.
I'm about to play the game some more tonight. I'll also try the Control Panel app and see if I can boost Gamma while I play, then lower it back down.
UPDATE: this configurator version has 5 values in the pulldown, and they are represented by the numbers 0 - 4 in the reg. If I change the 4 to a 5, it freaks out SiN and all screens are black. I'll try the Control Panel and see what happens. Thanks again for the tips!
UPDATE: what seems to work is... to leave the NVidia Control Panel open to the "Adjust desktop color setttings" panel" and when I get to a dark area of the game, ALT-TAB to the panel and increase the Gamma to 1.6 or so. Have to set it back afterwards, but since the panel is open on the desktop when I quit the game, I only need to hit the CANCEL button to return to normal Gamma. A hassle but it works.