Is "0" the uncorrected setting for "Full Screen Gamma Correction"?

[AmiableApkallu]

Under "Display Settings" there's an option titled "Full Screen Gamma Correction". The setting defaults to "50". Is "0" the uncorrected or intended look for the game and anything above 0 a compensated gamma setting?

The intended look is described right there under the setting: "Recommended level: x is not visible / o is just visible." Not described there is that you want the bars in white-to-black gradient to all be the same width / distinct from each other. (At the extreme ends of the setting, you might see the bars, especially at the left and right ends, "merge" together.)

Change the value on the slider until you achieve that.

The setting exists to ensure that you specifically can see the full range of brightness values, and that's going to depend on your monitor/screen/TV, the ambient lighting around you, etc.