The movie wasnt even THAT funny lol. Sometimes some people make it sound like a SNL sketch or like an adam sandler movie full of jokes .....
Most of the humor is the situations they find themselves in... Egon is always serious. The humor to me comes from his blunt and honest answers to things and lack of subtlety....
Winston never even says or does anything funny. he was the most regular character. Not even Ray did that many funny things.
Most of the humor, almost all of the humor comes from Venkman never taking their job and research seriously, his seducing of Dana and the humor comes from the receptionist Janine and from Louis Tully....
Sometimes people make this movie sound like ace ventura pet detective or something lol. If you focus only on the ghosts and only on the scientific research the guys did, as well as the Zuul plot, the movie is pretty scary. Take all the humor out and you still have a sci fi horror movie underneath.