Corrected entry: When Eric and Donna are on the hood of the Vista Cruiser, their heads go through the non-existent windshield.
Corrected entry: Guys are sitting in basement, Fez is sent home by Red. While Kelso speaks, you can hear that Fez opens and closes doors. But in the next shot - Fez is standing in front of open door.
Correction: That sound is actually Red opening and shutting the door they use to get in and out of the basement, not Fez.
Correction: There are views where you can see reflections off the windshield and you can also see them "propped" up by the windshield. The windshield is definitely there. The shot never cuts away from them so the windshield remains there. The "non-existant windshield" is, as stated, an optical illusion.
Zwn Annwn