Unlike this episode, Chibiusa did not appear as Sailor Chibi Moon until the middle of the third season of Sailor Moon (1992).
In the original series, Death Phantom never turned into a massive wave of darkness, nor was he one with Nemesis itself.
During Death Phantom's monologue of his fusion with Nemesis, Sailor Jupiter's hair is accidentally miscolored a bright red.
During the original Black Moon arc, Chibiusa was restored to her former self when Sailor Moon became Neo-Queen Serenity and reawakened Chibiusa's real memories.