In previous episodes, castle has made it clear that he hates when people misuse the word irony, yet when he holds up the paper and says, "talk about irony!" when in fact the heading was not ironic, it was just coincidental.
When the female murder victim is found on the carousel, her eyes are open and rolled up, and her mouth is slightly open. In the next scene, when Lainey is examining the body, the victim's eyes and lips are closed.
When Castle arrives at Beckett's apartment with a bottle of wine, he pours the wine and announces it to be a Chateauneuf du Pape, A Chateauneuf is a red rhone (which is packaged in a burgundy bottle); however, the wine Castle pours is from a Bordeaux bottle.