Nope... this didn't work for me.
I fully ran through episode 1-5 seven times and it did not pop...after 7 full runs, I ran it 10 more times killing only the first knight at the bridge, crossing the gaps until I got a checkpoint and reloading. That did not work either.
In the end, I read another thread and tried episode 3-3. At the start of that mission, 3 flying guys come out of a hole in the wall. I blew up as many as I could, finished off the room real quick, and ran up the hall to a checkpoint and restarted the level. On my 4th restart, it popped.
...now I am going to go grind 2-4 for a bit until I get 145k tech and pray for greasemonkey...