When fighting King Shark, Batman attempts to use a spray labelled "Shark Repellent". This is a shout-out to the 1966 Batman movie, and the 1958 comic Batman #117.
"Darkseid is... leaving" is a play on Darkseid's oft-stated declaration of inevitability in the comic books, "Darkseid is."
Sy Borgman's design when plugged into the TV, references Max Headroom down to the similar-styled glitchy speech patterns.