In the original series, Usagi never used her disguise pen again after the second season. However, Sailor Venus used it once to deceive the Death Busters to think that she was Sailor Moon.
Each member of Witches 5 made her own appearance one after the other in this series. They were never shown all at once in the original series.
Hotaru was never aware of Chibiusa's identity as Sailor Chibi Moon until the fifth season of Sailor Moon (1992).
After Sailor Moon had defeated the Daimon, the animation of the Daimon Egg coming out of the cat was very reminiscent to how Daimons died in the original anime's third season.
Mugen Academy did not have an amusement park or any other place named after it in Sailor Moon (1992).