Continuity: In the first Hellboy movie, when they first show the BPRD headquarters, it reads "Newark, New Jersey". In Hellboy II, they show what is clearly the same highly distinctive building, but it now reads "Trenton, New Jersey".

Continuity: After the golden army bots awaken, it zooms out to show how big the army is, when they do the prince and princess disappear in the background, then reappear.

Continuity: In the scene where Hellboy and Abe are getting drunk by Liz's bed, one shot shows the tab on HB's beer can pointing up. In the next shot, the tab is folded down.