Deliberate mistake: Although the first account of what happened in Zhao isn't completely true, the arrows penetrating the calligraphy school are sometimes flying at angles that make their trajectory impossible, such as arrows flying perpendicular to the ground or even flying upward.
Hero (2002)
1 deliberate mistake - chronological order
Directed by: Yimou Zhang
Starring: Jet Li, Donnie Yen, Tony Chiu-Wai Leung, Tony Leung Chiu Wai, Ziyi Zhang, Maggie Cheung, Zhang Ziyi
Visible crew/equipment: When Broken Sword and Flying Snow are walking in the desert to the place they want to hurt themselves, the shadow of the crew is visible on Flying Snow.
Flying Snow: Since you wish to die, I will assist you.
More trivia for Hero
Question: In the final fight between Flying Snow and Broken Sword, how did they get their weapons back? Weren't their swords still in the palace?
Answer: Those were two different swords they had at the end. You can tell because when Broken Sword's weapon hits the sand when he drops it, you can clearly see the tapered point, not a broken edge.