Nearing the midway point, when Candy has disrobed for General Smight, and she is shown from the rear, she appears to be completely nude. However, when shown from the front, a slim strip of her panties can be seen on her right hip. (This comment is from the generally available edited cut in the United States of 101 minutes, so may not be an issue in the full version of 124 minutes.)
In the closing sequence, when as Dr. Krankeit is giving the middle-aged men injections that restore their youth, all of them emerge as children, with appropriately oversized clothing. However, when he injects himself, his clothing re-sizes to fit his new child's body. Also, he retains his adult's beard.
Towards the end of the operation scene, as Dr. Krankeit mentions that he is resting his left index finger against an important part of his circulatory system, "fully three inches inside" the patient's head, and that the slightest error could seriously reduce brain functionality. But when he withdraws the hand, he is holding up his middle finger. He continues to prominently 'give the finger' to the audience until he exits the room.