And it ocurred to me, I'd been playing the game at that brightness for three years, but how do I know if that was how the devs intended it to be seen? I could have been playing all my games much darker than everyone else, who all have cheery bright gameworlds in comparison.
One nice feature I run across sometimes in games is a "test" screen for Brightness/Contrast. It usually shows up as a picture, and words saying "adjust your brightness/contrast/gamma/whatever until the image is barely visible against the black background". It's nice because it allows you to set things to how the devs actually intended it to be.

(of course, that may end up being too dark or bright, but at least you have a defined baseline to work from.)
Most recently, I saw something like this in the PS3 demo of Dungeon Siege 3.
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Personally, I'm not a fan of really dark. Don't want to turn stuff up too far, because it screws up the colors, but I do tend to push the brightness up a notch or two in games where the darkness isn't a specific feature (like suspense games.... the dark is there for a reason. :tongue:)
What I especially don't like is games where there's rapid shifts of contrast between very dark and light areas. It may be more "realistic", but it's hard on the eyes. Nier did this a bit, with the dynamic lighting (when you were in shadow it darkened the whole view, when you stepped into sunlight you got hit by glare until your "eyes" adjusted.) Also saw this in some youtube videos of one of the current modern warfare style games - super dark shadows with super bright sunlight whenever you stepped in front of a window or out of an alley.