Superman is frozen, but his cape still flutters freely in the air.
Kryptonite is supposed to be the only material that can harm him, end his super powers, or kill Superman if he is exposed to it long enough. Therefore, this episode goes completely against the one threat to him that everyone knows from the original storyline.
Dr. Watts states that his invention will lower the temperature to 2000 degrees below zero. This is not possible, as no temperature can be less than absolute zero which is -459.67° on the Fahrenheit scale (-273.15° on the Celsius scale).
When an envelope is slipped under Clark Kent's office door, he opens the door to look for the person who left it. He could have used his X-Ray vision to look through the door and walls without opening the door.