Continuity: When Prince Nuada holds up the golden egg-shaped "Forest God" pod, it's in his right hand. After it opens and he goes to take out the green object, he's holding it in his left hand and takes it out with his right hand.

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: When Hellboy has been speared in the chest and fallen to the ground, the POV shot of Nuala and Nuada has been turned so their heads are at the right hand side of the frame – from Hellboy's point of view their heads should be to the left.

Continuity: When Hellboy is climbing the "Hotel" sign, the letters that have been damaged change.

Continuity: After the bloke drops the bean to deal with Hellboy, the amount of flesh coloured skin on Princess Nuala's face constantly changes. (This is a different scene than the one at the market when they meet her for the first time.)

Plot hole: At the end of the movie, after the crown is whole and in Hellboy's possession, Liz decides to melt the crown down so no one could ever use it again to raise the Golden Army. But throughout most of the movie, Liz and her team had possession of one of the pieces of the crown. Why didn't she just melt that one piece when they had it? The crown never could've been put back together without it, and they would have never had to worry about the Golden Army.

Continuity: When Abe is with Princess Nuala for the first time at the goblin market, the amount of flesh coloured skin on Princess Nuala's face constantly changes.

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.