All four Ghostbusters drive to Lupusville in the Ecto-1, but at one point Ray asks Peter if he has any idea where they are, and he is suddenly sitting on the floor of the firehouse and not inside the car. Peter answers him from the front seat.
When Winston wakes up in a room lying next to Egon, the background is visible through his hair.
After the Ghostbusters leave Lupusville, Peter laments they didn't get paid for their services. However Gregor paid Janine a small bag of gold back at their headquarters earlier.