Why is the pix so dark??

Not having Blu-Ray player may be the reason but why is the overall picture so dark ,,to the point of losing significant plot points..? Yea.. I expect caverns to be dark..but surely there is way to sell/tell the story in an enlightened manner. This is true in the 'Big Head Room'..as the ampules,,streams of goo..and even the Big Head..are hard to figure out.. When using the computer playback the scenes show more detail...but why not increase the light level so all viewers..even the ones with outdated,,or just older equipment... to have a visually satisfying entertainment event. Several times i had to flashback to the theater experence several months ago..to sort of fill in the darkened scenes.. I am not saying one couldn't follow the storyline,,but a brighter scene setting would help.