Plot hole: The whole problem with the teleporter occurs when fly DNA is mixed in with Seth Brundle's DNA, starting his transformation into the Brundlefly. Brundle is on a hiding to nothing from the word go, and the fly is irrelevant. Humans are a walking talking mass of foreign DNA - we are host to one trillion bacteria all of which has a complete complement of DNA, as do various tiny mites that live in our hair follicles and all sorts of single cell organisms in our gut. If the transporter serves to mix the DNA of all living creatures which are in the transporter pod at the time Brundle would turn into a half-man, half-bacteria. Incidentally, DNA from a bacteria, an amoeba or a hair follicle mite would be just as 'compatible' with human DNA as that from an insect. It's quite a simple chemical, really.
Plot hole: Sarah breaks a mirror in frustration by throwing something against it. Then she buries her face in her arms and sobs. It remains a mystery how she managed to cut her hand so bad that it needed to be fixed with five stitches, as she isn't even seen picking up the pieces. (00:59:15)
Plot hole: Where did Bob find a knife to skin and clean the rabbit? And why did he leave the ears and front paws? (01:19:45)
Plot hole: At the end of the movie, snails collect on the apparatus on which Oliver and Oswald have set up a time-lapse camera to photograph their decaying bodies, eventually short-circuiting the camera and wrecking their experiment. As they had previously (01:34:18) set up similar apparatuses in the same area (Alba's country estate) photographing other decaying organisms, why didn't the snails collect on them? (Pleasant film, huh?) (01:52:45 - 01:53:50)
Plot hole: In the debrief in Viper's office following Maverick and Goose's first flight at Top Gun (in which they defeat Jester), Viper states that "Commander Heatherly lost sight of you and called no joy." However, during the actual flight scene, you never hear Jester call "no joy." I've always assumed that this part of the scene was accidentally left in the editing room.
Plot hole: When Jeannie encounters Mr. Rooney at her house, she attacks him and calls the police. Later, the police pick her up for filing a false report. Why? Surely they would've seen signs of an intruder such as a dropped wallet on the floor and footprints in the mud right next to the house.
Suggested correction: Without knowledge of what happened when the police visited, it's impossible to call this a plot hole. It might be that the police knocked on the door, Jeannie answered and explained that by the time they got there the intruder had gone. She could have got angry at them like she did on the phone. Maybe they arrested her there and then, without entering the house or searching the grounds (for someone they'd just be told was no longer there). Who knows? Unlikely sure, but not impossible.
Plot hole: Kelly is a friend of Jason's from LA and they have been seeing each other since he transferred to Seattle (he mentions 'the other day' she saw something at the pet store). Basically the one passion in life Jason has, is karate. Her brother is the US karate champion, and yet Jason didn't know that or even that he was from Seattle. That's absurd on several levels, since it implies that he wouldn't know her last name (then how did they stay in touch?) and they never ever talked about anything personal, because it's fairly obvious it would come up really easily.
Suggested correction: Being as how the bacteria and mites and such were IN or ON Seth, the machine was able to organize those symbiotic relationships accordingly as teleporting one would teleport all. The fly was separate, not touching. The machine was not programmed to anticipate two separated entities and so combined them into one on the other side.
Phixius ★
We leave behind a vapour trail of bacteria and viruses (among other things) as we walk, in our breath and emanations from pores in our skin, and Brundle isn't trapping any in his clothes as he isn't wearing any. Brundle has an invisible cloud of DNA floating around him in that teleportation chamber and as far as the machine is concerned their DNA has exactly the same status as that of the fly.
We don't know enough about how the machine works to determine how it might differentiate different DNA types. Unexplained science means it's somehow able to do it. Willing suspension of disbelief for the win.