Continuity mistake: When Hatta Mari captures Daffy Duck, you can see the gun she is holding has a funnel-shaped muzzle at the end of it. But when Hatta says "Give me that secret!", we cut to Daffy and the muzzle has disappeared. The muzzle reappears when Hatta takes Daffy after he has swallowed the secret.
Continuity mistake: Watch Daffy Duck's bag when Hatta Mari kisses him. When Hatta kisses Daffy, he melts and you can see the bag is standing up, but when he slides down the stairs in the next shot, it is now lying down and the handle is completely different. In the next shot, the bag is its normal self and Hatta picks it up and unzips the top, but when Daffy emerges from the hole, the bag is back on the floor again.