Factual error: In every scene where knights collide on the lyst, you see their lances in one hand and the reins to their horse in the other. When knights jousted, they would drop their reins before impact so that a severe impact would not cause them to jerk the reins or become entangled in them causing more damage to themselves or the horse.
Factual error: Ulrich's armor repair is either gas welded or arc-welded, not Forge welded. Forge welding is the only type of welding available at the time and is usually extremely different if even noticeable. (00:35:10)