It's pretty hard in UV but I made it, and I am not the greatest player either. Yet I must not play doom on lower difficulties than UV ;)
I ran past the Cyberdemon. Would have been easier if I kept that invisibility secret for the end.
Yeah I didn't put that Cyberdemon there to be killed normally, just as an obstacle. There's a secret that kills it, tho, to allow a 20/20 run.