Revealing mistake: During Sebastian's aerial act where he performs without a safety net, he misses the trapeze bar and falls. It's obvious that he lands on a recessed safety air cushion disguised to look like solid ground. It deflates slightly just as he hits it, and the shot quickly cuts away.
Continuity mistake: The pictures on the wall of Calvero's apartment move around during the scenes, particularly the photos flanking the clock on the mantle above the fireplace. A particularly striking example is during the scene wherein Terry recovers the ability to walk. The scene starts off with a photographic-profile-portrait of Chaplin (not decked out as Calvero the Clown) on the left side of the clock and on the right side of the clock, a full-length photo of Calvero the Clown wearing a straw hat, and leaning on his cane, which is held in his left hand. As the scene progresses, the portrait to the left of the clock is replaced by a half-length photo of Calvero the Clown wearing a top hat, with his cane swung across his body, angled up. As Terry realizes she can walk, the portrait re-appears to the left of the clock, and there is nothing to the right of the clock.