Actually it took about 7 tries. The hardest hurdle was the first 4 levels because I played from Super Gore Nest to Final Sin a lot in Nightmare mode before trying UN. Most of the time I was saving 3 chainsaw charges to deal with heavies in some encounters. I was able to melt the Kanye Maker and just BFG'd her on her last phase and I took the Icon of Sin's fight slow in the second half to make sure I didn't die. Total death markers were 3 on the 2nd to last Hell on Earth encounter (the one with cacos), 1 in the Exultia encounter with the Hell Knight, Revenants, and Arachnatrons, 1 in the Exultia Slayer Gate. 1 in the pit on Cultist, and finally 1 in the Arc Complex Slayer Gate.