Revealing mistake: When making traps, he's harvesting powder from a spent shell (primer has been struck). (01:05:50)
Revealing mistake: As Liam Neeson looks at the money in the bag, he turns it over and it says "motion picture use only" on it.
Revealing mistake: The jaguar near the start jumps onto the bar and prowls along it. It knocks over one glass with some force, which shatters, but the second glass is barely tapped by its foot and it smashes to bits too, when it should just have been pushed out of the way.
Revealing mistake: When Finney is looking for the bike lock's combination written on the wall, the distance between the mattress and that wall (several feet) can be seen. However, the next time Finney wakes up on the mattress, the mattress is against or almost touching the corner, but the mattress was not that close to the adjacent wall. Furthermore, when the Black Phone rings, the mattress is the same distance from the phone as it originally was (which would be several feet away from the wall). (01:04:59 - 01:10:53)
Revealing mistake: Deacon uses "hidden" food to get the dog to come up to him. The "treat" is largely concealed - but the dog's slobber gives it away. The camera shifts after Deacon's hand goes next to the dog's mouth, giving the impression that Deacon is just petting the dog under his neck. (00:06:35)
Suggested correction: He was feeding him. You can see him eating out of his hand. The food isn't "hidden" You can hear the dog sounding as if he were eating something and his face is in his hand. Those were added sound effects in post. At first glance I got the impression he was giving the dog a treat as they were pals.
Part 1: Based on the circumstances plus Deacon's actions immediately before, during, and after his encounter with the dog, I believe it was a lousy attempt at luring the dog but trying to give the impression there was no lure (food). Deacon did not have food when he came out of his house and wasn't expecting the dog to be there. Deacon even pointed his right fingers toward the dog when he said, " You [are] the one [who has] been gone for the last two weeks." Deacon stoops down and [continued].
Part 2:...makes an effort to point his right hand fingers downward, again giving the impression he wasn't holding anything (food). If feeding a hungry, cautious dog, I think he would have displayed the food in the palm of his hand (what is there to hide if actually feeding the dog?). When "sneaking" the food into the dog's mouth, a small piece can be seen falling to the ground. Deacon holds the dog under his neck, probably to keep the dog from reaching the food that has fallen.
Part 3: (The dog later picks up the piece that fell.) Taking all these odd movements into consideration, I'm sticking with my assertion - Deacon "surreptiously" lured the dog, but his actions were noticeable, thereby revealing what was actually happening. Also, if the dog was missing for two weeks, Deacon would not have been likely to bring food out for the dog that morning. Anyone wanting to view the scene and serve as a tie-breaker, start at 00:06:26, watch Deacon's right fingers @ 0:06:32+.
Revealing mistake: When Bloodsport rescues Ratcatcher 2 from on top of the car, they don't actually dodge the arm coming for them but are going straight through like it's not even there. (01:54:16)
Revealing mistake: When the military security checks Flash's phony badge, the name on the personnel list to the right does not match the fake identity; Barry's false identity is "Rowe, Wesley", but in the list the name "Band, Ryan" is highlighted. This mistake was not present in the theatrical 'Whedon' cut where the name was altered to match. (02:27:05)
Revealing mistake: When Jake is sliding on the floor at the mall trying to grab his retainer, streak marks are visible on the floor from where they practised the shot.
Revealing mistake: At Wendy's 50th birthday party, the helium balloons did not move, even when her daughter Liz walked next to some of them while carrying a birthday cake with lit candles. (00:01:44)
Revealing mistake: The picture on the wall of a younger Mike on a horse shows his groin against the horse's neck right below its ears - obviously photo-edited/photoshopped. (00:04:29)
Revealing mistake: When Knox pulls up behind the parked BMW, the BMW's red tail light reflectors are not real (and maybe the car isn't, either). The reflector on the right side, in particular, is not fully connected to the car. (00:03:55)
Revealing mistake: When "Snowball" is sleeping on Lena's bed, it is obviously a "stuffed double" (stand-in). Snowball is usually partially hidden behind the dog (so breathing doesn't need to be shown/mimicked). The failure of Snowball to make even a slight movement is a giveaway (e.g, no ear movement when Lena starts talking), but even the stuffed lion, in itself, is not a very good replica - it simply looks fake. (00:33:44 - 00:48:20)
Revealing mistake: The blue framed window the girls walk in front of after exiting the VW bus parked along the curb is presented as part of an extension of the house, but not when there's a front view of the entire house. The windows are actually aligned with the front door. (00:11:44 - 00:15:00)
Revealing mistake: If you look at the drawing in front of Eddie when he glances down at it after Venom typed in the name of the beach, it's only a crude draft of the one in close-up (it's missing the wave lines below the cliff outline, for instance). (00:11:20)
Revealing mistake: After he takes his plate carrier off which looks suspiciously light, the rest of his armor is air-soft gear meant to stop BB's, not high power 5.56 rounds. (01:43:00 - 01:45:00)
Revealing mistake: After Jamie told Scottie, "Dad would have been proud of you", she was shown against a mountain background - but she was in the woods surrounded by trees. (01:06:15)
Revealing mistake: When Teddy's Cadillac Seville is blown up, you can see that the engine, transmission and catalytic converter have all been removed.
Revealing mistake: The staircase to the second floor bedrooms is awkward, not in proportion to the rest of the house, and usually only the section that is needed for a particular shot is shown (and the section is most likely a replica). In particular, the staircase would be quite steep - and extend well into the attic! - if the upper portion continued at the same grade/angle as the lower steps. The perpendicular entrance is too short and both posts are not always on the floor (one may be at the end of the steps). (00:23:04 - 00:28:12)
Revealing mistake: While Martin is being mauled on the ground by Valentine the zombie tiger, he is being thrown up and down and side to side. There are a few seconds where the tiger takes a small break and watches him try to crawl away, but his body is still swaying around as if he still being grabbed by the tiger, but the tiger is not touching him; they did not match the animations of the tiger with the physical acting of the actor properly.
Revealing mistake: During the attack on Druig's village, there's a shot of Gilgamesh and Thena running towards the camera, then stopping as two Deviants fly over them. During this scene, you can see Don Lee (Gilgamesh) briefly look straight at the camera (he's not looking at either the village or the Deviants, since they headed in the opposite direction). (01:13:50)