Notably Adam climbed the route without knee pads. While there are not many knee bars on the route, there is an important one through the crux which takes it from 8A+ to 7C.
9b standard for me? I wish! No, 9b is still a really hard route, certainly not something I would do in an afternoon without too much effort. To tell the truth with Iron Curtain I thought the process would be quite easy and quick. I felt super strong, on the way to Flatanger I had just fired a 9a project called Purgatory at Hell (an area close to Trondheim) on my 2nd go, and the first day on Iron Curtain felt good. But how wrong I was!
Bad conditions arrived and I discovered that the crux holds were completely wet due to condensation. Conditions improved, but were far from perfect and it's hard to climb a route this hard in bad conditions, there is no margin for mistakes and I kept making them... In the end, after some days trying, an extremely strong wind made me go up into the cave yet again despite wanting to take the afternoon off and I sent this perfect line.
References
[1] https://www.planetmountain.com/en/news/climbing/adam-ondra-frees-new-9b-at-flatanger-in-norway.html
[2] https://www.instagram.com/p/-JGf-oAumJ/
[3] https://www.instagram.com/p/7AJU5ugugO/