When Lana and Clark are sitting on the Windmill and the camera
is facing them close up you can see the shadow of the windmill moving in the wind and the windmill behind them moving but when the camera zooms out for the last shot the windmill is still.
Chloe is taking a poll, and when we see it in close-up, the paper is white. But after she writes down Lana's answer, the page can bee seen as being a yellow legal pad.
When Lana and Whitney are talking in the school corridor after Lana becomes infected, Lana's hair changes from swept back to falling forward between shots.
When Johnathan Kent and James Beales are driving in the beginning of this episode the road changes from a two lane with paint to a one lane with no paint.
About 10 mins in when Martha and Jonathan are in the kitchen you can see a cupboard in the background open its doors mysteriously.
Somehow Pete's symptoms begin immediately after his exposure to the flower, even though Lana and Jonathan took a while for their symptoms to show up.
Pete Ross could not have shot Lex Luthor even if he had tried. He had already shot his six-shooter 6 times.