Darkness in multiplayer shooters is a tricky one. In theory, it demands new ways of moving, more attention and more caution, but opens up new tactics and opportunities. In practice, people bump their brightness high enough to make the darkness pointless so you do it too because they’re essentially playing a different, easier game and then it’s all just pointless and everyone’s looking at an ugly, ugly game. Few games manage fun, uncheatable darkness.
Military FPS Insurgency is having a crack at darkness in its next update, named Nightfall. Along with spooky night-time maps, it’ll bring a new co-op mode about sneaking around in the dark.