Revealing mistake: Two scenes after the opening credits, West fights the strongman Titan. When Titan throws West (who is horizontally positioned on Titan's shoulders) down to the ground through the circus tent, a mattress upon which West lands is mistakenly exposed.
Revealing mistake: Tony throws two knives at West - but on the wall where the knives hit, the rectangular openings from which the blades actually emerge are delineated beforehand. Happens again a few scenes later, where slots cut in the door are already there before the knives are thrown. [Spoiler: It's inconsequential to the "revealing" error, but if you play the scene in slow motion, you can see that both times, the knives pop through from the back of the "wall." This is also how the carnival trick is performed.]