Slimer is seen sleeping with his Stay Puft doll.
When Slimer hears Jim Venkman, he thinks it is the Boogieman at first.
Peter's father's first name is revealed to be Jim by Winston.
While explaining the SCEP-TECH and the way to defeat Quetzalcoatl, Egon uses the "Psychomagnotheric" term first coined in Ghostbusters II (1989).