Reality + Fiction = Half Life
Why? Simple, Half Life combine the movie style and game style to be a perfect game. The story is that our hero is a lab geek work for the Goverment to do secret. One of their experiment have gone awire bring the aliens to our world and the chaos rule. You most help your friends to resolve the problem, What the Hell Happen!! To get the things worse the Gov send they best soldiers to take down the threat. The Soldier aren't the bad guys, they just follow order which is to kill everyone and you to.
This is the cool part, The enemy have great AI, you reload - they reload, solve puzzles and save the world but first save your rear.