Cindy looks shocked before she clocks Greg smoking a 'real cigarette.'

In the bedroom you can see the poster in the wideshot behind Marcia in Cindys close up (though the lamps have been changed).

Carol follows Mike upstairs but we do not see her pass even if you look at the gap in the door frame. I suspect she went into the room at the top of the stairs.

Look at the right handle on the closet door behind Mike when he is talking with Greg - it seems to have slipped down. It is repaired during a later scene.

In the kitchen during a scene with Carol, Alice reaches for the same plate twice (once in the wideshot and then again in the close up).

We cut from a close up of Greg and Tommy with no one in the front door way straight to a wideshot where Tommys mother has already entered the hall.

During the tag you can see a table behind Greg in the hallway outside the parents bedroom when we should actually see at least a side of the door to the boys room.

If you were Greg and your parents believed you about the cigarettes would you then make it impossible for your friend not to confess that they were his?