Fracture

Ok, so here's the deal with this one. It is glitched, but only if you stop playing the level and return to it later. Once you get to the Washington DC Intro level DO NOT STOP PLAYING until you beat the game. Act 3, including the final boss, must be done in one playthrough. VictimOfDesire suggested this was how he finally got it to pop, so real credit goes to him, I'm just putting the guide up. Hope this helps anyone, as I was frustrated after beating the game and not getting this or the Hardcore one. After making it back to the initial part I had stopped in the first time, this and hardcore popped about halfway through Act 3.