After Jimmy and Lois are flying like Superman they come in for a landing. Lois' shoes are missing the sharp points on the heels and they are not very high, making it easier to jump into the scene. A moment later, the sharp points are back on her heels and they are now higher.
As Clark exits Perry White's office, he is wearing his hat. Once he enters the hallway, the hat is nowhere to be seen.
In stop-motion, it's clear that neither sandbag even touches Jimmy after Professor Pepperwinkle releases them from above, but he's supposedly knocked out by them.
In the diner with Lois and Professor Pepperwinkle, Jimmy says, "Nobody's listening." Then he rises slightly and glances over the divider, to see if anyone's in the adjoining booth. The two crooks are, but both are sitting on the side closest to Jimmy, with their backs to him. When he glanced over the divider, he wouldn't have seen anything but the top, and perhaps the back, of their heads. However, during his knocked-out dream sequence, he sees both men full-on. After he comes to, the crooks arrive and he recognizes them, saying, "Oh, no! I thought we left the two of you tied up at the warehouse."