Other mistake: After the ghost "possesses" the building and blows out the windows, no shards of glass or debris land on the Ghostbusters as they get up to escape, even though there was plenty of time for the glass and debris to rain down on them.
Suggested correction: You can plainly see that the debris is actually flowing upwards in defiance of gravity. Spectral energy is running amok and the laws of physics are all over the place.