I work on a cathode ray tube-- the most superior of all display devices-- however, most people use LCD moniters, and they are bright! Brighter than I want my game to appear on their screens! Is there a way to configure everyone's screens to the brightness level I want?
Most brightness controls are on the monitor itself, with no software interface. At least not a universal one you can program without proprietary software.
You could do one of those brightness things, where you tell the player to turn down the brightness until a symbol is barely visible but for in game brightness controls, other than like making a big transparent black square over everything I can't think of a way you could do it.
Well I guess I will just have to steal a friends LCD and get some sort a dual monitor setup going-- so that I can be conscious of how it looks both ways-- because I really love my CRT, but I am in a minority !
For sprites you could use a color filter. Just add all the sprite objects to a family,add a variable, then set the family color filter to rgb(variable,variable,variable). With the slider changing the variable to 0-255.