When Kara and Lena are on the couch eating doughnuts, the glazing on Lena's doughnut seems to change colour between shots.
When fighting Metallo the first time, he shoots a continuous blast, but when Supergirl is shown, the blast goes by her in multiple shots.
Henshaw declares that "Kryptonite is usually the most stable of elements", but kryptonite is radioactive-- the opposite of stable.