So a shooter has to be flashy, bright and like that?
Watch band of brothers, watch Saving private ryan, they are also very gritty and filmed with a certain colour palette. And that film and that series are excellent.
They made a choice to make the helghast planet a grim dark one. I can't see why this should the reason to bring the game down. If it fits the game, then it fits.
And to answer your topic question: Why would one invade a country / planet that has just tried to invade you? To end the threat.







