Plot hole: In the scene where Lewis and Clark nearly hit the Event Horizon, One of the crew is calling out the closing distance and another confirms this information. Regardless of clouds obscuring their view they were aware of their proximity and the fact that they were speeding towards it and forced to attempt an abrupt stop makes no sense.
Plot hole: It is highly unlikely that the murderer knew Phil was going to put his ear to the stall when he heard the babbling. It is even more unlikely that the murderer is going to get him on the first stab through the stall. (Which also requires a lot of strength). We also have to assume that he spent time hanging out in the bathroom knowing Phil would go there to begin with, and that other two men with weak bladders were doing the same simultaneously forcing the victim to go to the stall to begin with. (00:07:45)
Plot hole: In the opening text scroll, it is said that the creatures live in the dark, and the name of the movie is "Alone in the Dark". But at the very end (when Edward and Aline are walking around the deserted city), the camera zooms in on the couple suddenly, implied they were attacked by one of the monsters, but in broad daylight.
Plot hole: When the fog finally hits the lighthouse and is seeping in, the generator is hardly audible vs. how loud it was when it was first started.
Plot hole: When Freddy takes over Jesse's body at the party, there are several people watching through the patio doors when he confronts Lisa. None of these people ever make a sound, even when they see Lisa have a knife fight with a horribly disfigured man with long knives coming out of his fingers. The other party goers are completely oblivious to Freddy's presence until he comes jumping through the glass doors.
Plot hole: When Gallagher is trying to kill the senator at the end, he is fired on by his bodyguards. Yet when they finally catch up with him, they're quite content to stand back and watch him torch the senator. One of them even lowers his gun. They couldn't have known Gallagher and the senator were aliens. (01:27:20)
Plot hole: The creature gets caught in the fishing net and (after a struggle that shook the whole boat) freed itself. The scientists, upon drawing up the net, find one of the creature's claws, and thus they now seek its source. Shortly after, while Mark is busy loading a harpoon gun, Dave is protesting, stating, "This...this thing *alive* and in it's natural habitat..." It would seem that at this point, they know the creature is *not* dead, but very much alive. They dive, they see it, Mark shoots it with a harpoon, and then upon surfacing, they argue a bit before reporting what they saw to everyone else. So why after seeing it underwater, fully knowing that "this thing (is) alive," do they act so surprised to see it, as if they didn't have a clue it could possibly still exist?
Plot hole: Mun has an eye transplant, and this gives her the ability to see the dead. However, how come she can also hear the ghosts as well?
Plot hole: After the scene of Rachel as a child, there are six days worth of events in what should be five days. Monday Lisa kills herself. Rachel works at photo hut. Tuesday Jesse and Tracy have sex, Walter is hit by car. Wednesday Rachel stands Jesse up because Mark and Eric have come to her house. Thursday Jesse and Rachel's first date - no sex. Thursday again Eric meets with the DA and Jesse and Rachel have sex. Friday is the game and party.
Plot hole: The reason given for the cop having psychic powers is that he has a well-developed hypothalamus - but that is the part of the brain responsible for homeostasis (maintaining a constant internal environment for the body). So even if you had a particularly well-developed one, you might sweat more when you get hot but how could it make you psychic?
Plot hole: When Nosferatu is caught in the sunlight towards the end, his reflection can be seen in the tall standing mirror in the corner of the room. This makes no sense because vampires do not cast reflections. Deliberate or not, in the original Bram Stoker novel, there is a scene in which the character Harker is shaving, and is disturbed to see that the Count casts no reflection. There is also a passage that states, "He throws no shadow, he make in the mirror no reflect." Some would argue that the rising of the sun robs him of his powers, giving him the reflection. But his reflection is visible before the rooster starts crowing, before the sun even rises.
Plot hole: One alien egg is shown hanging from the wall at the start of this film, yet there's no way it can be there. The queen didn't take any with her from LV426 in 'Aliens', and if she did, she had no opportunity to place them on the Sulaco between exiting the dropship's landing gear, engaging Ripley and being killed.
Plot hole: Why did the killer cut off the hot water? Did he think that Dorothy would come down and turn it back on herself with all those staff members in the house?
Plot hole: When Ana is driving away from her home, she stops on the road and a guy opens her door, scaring her into turning her car toward the curb, plowing through a guardrail. She couldn't have picked up a lot of speed, and those guardrails are supposed to always be reinforced on highways/interstates. At that angle she would have had to knock out at least 4 reinforcing beams (they use 'I' beams to reinforce them, and are intended to stop vehicles from passing through them, or slow them down immensely).
Plot hole: Spoiler Alert: When Finney gets the rope that was hidden in the wall, he needs to thread it through the window bars about 8 feet above his head. After trying to lasso the rope through the bars, he grabs a rolled-up carpet and threads the rope from the bottom of the carpet through the bars and it wraps itself around the bars. There is no way a rope (or even a bendable cable) would be able to thread itself 8 feet through a carpet. After he grabs it, you can tell it's a loose rope, not a stiff wire. (00:51:15)