Gamma level changning issue

[Onyx]

Hello, when prompted to change gamma on installing the game or in the options menu, i can only temporarily set the gamma to desirable level. After releasing the mouse from the slider, it resets the gamma back to the center.

Is there any manual way to set the gamma?

P.S. I'm using an ati card

[Yuhaney]

I don't have the demo installed right now, but I think the setting file is same as was with Penumbra games...
But try this: find file called: "settings.cfg".

Open it into any text editing program and find "Gamma="X.000000".
Change the X into any number you want and save the file.