Megatron's first line is "Decepticons, I have returned!". Appropriately enough, this was the first time since 1987 that the character had been voiced by Frank Welker, so the line can be interpreted as alluding to his return to the franchise.
Cliffjumper has bull horns on his hood. Dwayne "The Rock" Johnson, who voiced Cliffjumper, called himself the Brahma Bull in wrestling and has a bull's skull tattooed on his arm.
Jack says "what's the first rule of robot fight club" "don't talk about robot fight club." This is a reference to the movie "Fight Club"