I found another one! :D
On that level, where archers stand on high placed red plank you have to climb the blue stair thing.. umm. the point is that you can go under that blue stair and jump in it mario style, you wont fall down if you keep smashing into that blue stair, you can climb like that and walk(jump) under red plank, where archers stand, and you can even kill them through that plank. I dont know if you already fixed that. Just want to help :P