After the kidnapping, they kidnappers are trying to remain unnoticed but they drive through the streets at high speed in a plumbing van.
The drawing on Peter's face suddenly vanishes during the kitchen scene.
There's an issue with it being wee morning hours in the dark, then day light, back to dark again even though this was between 330 and 530 in the morning.
In the beginning of the movie, Joey racks a round in her automatic pistol before getting into the black SUV with the other characters. Later, in the trap mansion, after Rickles and Joey have a conversation, they both rack rounds into their automatic pistols. However, Joey's pistol does not eject the prior loaded round from when she entered the SUV at the beginning.
Frank gets impaled just above his knee with a wooden stake. Once the stake is removed and the leg bandaged, he walks with only a minor limp and even outright runs at points, when his leg would be incapable of supporting his weight at all.
Trackers do not have flashing lights, would defeat the purpose of a stealth device. They put the device so it is it clearly visible as you approach the driver's side with the light blinking.
Sammy watches the Woody Woodpecker cartoon, Pantry Panic (1941) in her room, and judging by the audio, the cartoon order seemingly jumps around at random.
Unless Abigail had recently gone on a murder binge of truly epic proportions, it would be impossible for all the dozens of bodies at the pool that Sammy falls into, to be all so fresh, and for all of them to be seemingly in the same state of decomposition specifically if they have been sitting in a pool of water. However since Lambert was also at the house and it appears that the property has some history for Lazar, it may be that they and other vampires use that house as a "dumping ground" for other bodies, rather than leaving the bodies where they died and risking attracting attention. It could also be that the draining process gives some vampiric properties to their blood which acts as preservation but not enough to turn them.
When Abigail is loaded into the van after being kidnapped and drugged, Joey checks her pulse,. As Abigail is a vampire, and therefore deceased, she would not have a pulse. However, there are other vampire myths that are shown to be false, like the effectiveness of garlic and crosses, so it could be that this was a myth, as well.
Lambert collects seven cell phones into a bag, but when Joey takes hers from the bag it seems that it's the only one. Actually hers is just the one on top. The back camera of at least another cell phone can be clearly seen.
When Frank cleans his glasses after killing Lambert, a large drop of blood trickles up the wall next to Joey, revealing a reversed shot.
The crew goes to the mansion from which they kidnap Abigail with two cars, a black SUV and a van. They all leave in the van and leave the SUV behind. This goes against Lambert's extremely cautious planning.
It's too late to collect cell phones after they've already arrived at the scene of a crime, as the phones have already pinged local cell towers. However, given the true nature of the heist, this may be irrelevant.
All the kidnappers are supposed to be the "best of the best" but are all clearly street thugs with little to no experience.
There are at least 2 instances where Alisha Weir's natural Irish accent overrides her standard American accent used throughout the remainder of the movie, especially at the end as Joey is leaving her & her father. While it could be argued that that's her natural accent, then the inconsistency needs clarification.