In the gladiator scene, the punch Clark throws by jumping in the air is known as the Superman punch in MMA.
In Smallville s10e19 Zod rhetorically asks Kal-El if he knows the famous story about two brothers from the adopted planet: Cain and Abel. "Which brother are you Kal-El?" Interestingly, Tom Welling (Kal-El) later played Cain in the TV Show: Lucifer.
Final appearance of General Zod.
Clark mentions to Oliver that Darkseid probably traveled to other places before earth, this is true he travels to other planets and galaxies with what is called a "Boom Tube" which is a teleportation device, and he takes over the planet and turns all the sentients into his Parademons and turns the planet into the new Apokolips.