When Lex wields the gun against paranoid Clark, his grip and angling seem awkward. This is because it is held in Lex's right hand but Michael Rosenbaum is left handed.
Clark says he'll take Lana north to a place where no one will find them, this could be the Fortress of Solitude.
Martha and Jonathan learn about Chloe's knowledge of Clark's secret in this episode. This is also the first time Chloe uses green kryptonite against Clark.
The truck Clark wrecks is identical to the one he wrecked in "Slumber". This is the fourth time in five years that Clark has wrecked one of the Kent's trucks -- "Exodus", and "Delete" are the other instances so far.
Though its effect on him is slightly different, Clark is also subjected to the influence of silver kryptonite in the Supergirl (2015) episode "Nevertheless, She Persisted (2017)".