Continuity mistake: As Dave is leaning over the edge of the air boat with Rose behind him, he pulls a chunk of metal out of the water and places it on the edge of the boat on his left side. When he gets up from his lying position moments later, the metal is gone. Moments later again, with an overhead shot of the boat, we see what appears to be that piece of metal positioned at what would have been his right side, not his left. This is also where we see him step over the seat (twice!) in subsequent camera angles. (00:30:00)
Continuity mistake: When Lucas destroys Jake's statue, in the wide shots, the baseball bat on the floor is nowhere near a doll head. But in the closeup, it's right next to a doll's head.
Continuity mistake: When Josh has got out and they go looking for him, they find Aiden on a small bridge. From a distance he's got a very dark sweat stain on his shirt. In a closer shot it's faded to nearly nothing, and gets lighter/darker in different shots throughout the scene.
Character mistake: Ryan tells Jack that Darius turned into a werewolf right in front of his and Micki's eyes. Ryan and Micki never witnessed Darius' transformation into a werewolf at all.
Visible crew/equipment: When Michael Fay (1st Vampire ground zero) enters the cabin to escape the police, the film crew can be seen through the porch railing at the bottom right of the screen. (00:40:53 - 00:49:47)
Continuity mistake: When Marshall first finds Trip's letter, he holds it from the left side. In the close-up, he's holding it from the right side. (00:02:10)
Royal Jelly - S2-E1
Plot hole: It's all very well for Albert to humm "bzz-bzz" to indicate that he has been eating too much Royal Jelly and is no longer entirely human. But "bzz" is just the noise of bees flying, it's not a sound that they deliberately produce. It makes no sense to SAY "bzz." Suppose he was turning into a horse instead, then he might say "Whinny!", but he wouldn't say "Clip clop clip clop."
Continuity mistake: "The Feverman": Before putting the chain around his neck, the doctor removes both his detachable collar and his black string tie. A few shots later, not only is the collar back, but he's now wearing a red ascot-style tie. Both collar and tie vanish again one shot later. (00:17:05)