There are several differences between the series and the original film. In the City of Domes, there are no life clocks on the City-dwellers' palms, Francis has companions who seek Logan outside, the Sandman weapons are adjustable with a stun setting, the city is run not by a computer but a council of elders, they refer to the city as the "City of Domes," and there are many more people outside for Logan and Jessica to interact with. The City-dwellers also seem far more worldly and able to adapt to being outside than their cinematic counterparts.
The last 3 episodes of the series were not seen in the United States due to the show being canceled, but were broadcast in Great Britain. It wasn't until Ted Turner brought the MGM library were they seen on TNT in the late 80's.
Some of the props designed for the movie were reused for the series, Roy Hayes Visual Effects did the visuals specific for the series.
Rem was created to provide comic relief.