Goofs

(at around 1h 7 mins) When Kyle and Sarah escape from the hospital, they're both barefoot. Shortly afterward, when they're with John in the parking garage, as Kyle kneels, we can clearly see that he's wearing hospital slippers. In later scenes he's barefoot again.

(at around 14 mins) Early in the movie it is stated that only things covered in organic skin can travel back in time; yet the T-1000, which is entirely liquid metal, and John Connor, who is made of nanomachines, travel back in time with no problem. Although this is often cited in regards to Terminators like the T-1000, it may not be an actual continuity problem. It may instead indicate that poly-mimetic terminators clone actual living tissue on their bodies, also explaining why they have to go through naked like anyone else.

(at around 28 mins) When the T-800 is in the van it has no nose, however when reactivated its nose appears intact.

When Sarah, Pops and Kyle are going to the bunker, after they got out the trunk, both Sarah and Kyle were with shoes (and still with the hospital clothes), but when they are inside the bunker, walking, they were barefoot.

(at around 23 mins) When Kyle arrives in 1984, and runs into the T-1000 and asks for the year, the T-1000 slashes Kyle across his chest, leaving a bloody trail. But later that same day (at around 49 mins) when they defeat the T-1000 and they have the T-800 chip and are preparing to time-travel to 2017 (the "Did You Mate?" scene), the bloody slash is gone.

(at around 1h 27 mins) Heavy vehicles, such as school buses use air brake systems. When a loss of pressure is experienced in the system, such as when John destroys the air tanks, the brakes auto-apply. The bus would therefore come to an immediate halt, not continue on with "no brakes" as is seen in the movie.

In both Terminator 2: Judgment Day (1991) and Terminator Genisys, in several instances, our heroes fire grenade launchers at nearby targets on which the grenade impacts and explodes. High explosive grenades arm about 15-30 meters (45-90 feet) from the launcher after being fired. A grenade launched inside a small room would not have traveled far enough to arm and would not explode.

(at around 1h 12 mins) Four goofs when fighting at the MRI-scanner:

1: The window where the gas cylinder shoots through has no metal mesh in front of it, and there is no door at the entrance of the scan room. Both are essential parts to complete the Faraday cage the scanner has to be in. This to prevent magnetic or RF-interference from getting in or out of the scan room.

2: The magnetic field can't be switched back on instantaneously after hitting the emergency magnetic field release (quench) button. It takes at least a day and several thousand liters of helium to be able to ramp the field back up after a quench.

3: Almost all MRI scanners have active magnetic shielding to minimize the magnetic field around the scanner. This would make it impossible for the field to have enough strength to pull John back towards the scanner when he stand as far away from the scanner as he does at the end of the scene.

4: A CAT-scanner has its scanning array rotating around the gantry during a scan similar to what is shown when the scanner cover fails. The only part that sometimes moves when using an MRI-scanner is the patient table.

(at around 34 mins) In the car chase scene between the T-1000 and the protagonists, Kyle fires a 40 mm grenade from an under-barrel grenade launcher at what seems like less than 10 yards. 40 mm shells have a safety fuse which inhibits them from exploding at ranges less than 40 yards to avoid fratricide. This already was explained to James Cameron by his brother (who was a marine) after Terminator 2: Judgment Day (1991).

(at around 27 mins) When Sarah shoots the T-1000 after crashing through the store to save Kyle, she fires 13 shots from a Desert Eagle. This pistol carries a maximum of 9 rounds.

(at around 32 mins) Though previous Terminators didn't know how to build a time machine it is explained in this movie that they don't know who sent this one back to Sarah's childhood. It would be plausible for the person who reprogrammed the machine to add knowledge on building a time machine.

(at around 28 mins) In the first film, The Terminator (1984), Kyle Reese had no idea what the Terminator actually looked like, unable to defend Sarah until the Terminator "Zeroed In" in the Tech Noir nightclub. However in Terminator Genisys, Kyle Reese knew immediately that "Pops" is a Terminator when they meet for the first time in the armored van. However, Sarah already told him they took care of the terminator sent to kill her. So when Kyle sees "Pops", who looks identical to the terminator lying on the floor of the van, he naturally assumes "Pops" is also a terminator.

(at around 33 mins) Sarah and Kyle struggle to stop the T-1000 by shooting him through the police car's windscreen, instead of simply firing through the vehicle's radiator to disable the engine.

This will not work immediately as the car will still run for a few minutes before it overheats and THEN stops running. Shooting with hopes of hitting engine electronics\sensors\etc would give better odds of stopping the pursuit sooner.

Sarah and Kyle are pursued by their son, John Connor, despite the fact that, unlike in the original film, they never have intercourse to conceive him. However, they travel back in time once the first time machine is completed and have plenty of time to conceive John then.

When John frees Sarah and Kyle from the hospital they are clearly shown handcuffing the two police officers. Later when the other police arrive they are zip tied with giant yellow zip-ties.

(at around 3 mins) At the very beginning of the movie, during the introduction, a barcode is being read off of a person's arm. The laser beams go from one end of the barcode to the other, as if it were reading a line of text. That is not how barcodes work. The entire barcode is always read all at once because the thickness of the bars and the spacing between the bars are what provides the information stored in the bar code.

(at around 2 mins) The movie opens with a nuclear strike on San Francisco which pulverizes the Golden Gate Bridge - while in the foreground, a tree merely sways in the breeze.

(at around 1h 27 mins) Highly unlikely that a few of San Francisco's finest would have close to the same license plates. "99999x" and 99999y" watch for it on the golden gate bridge shot.

(at around 4 mins) In Terminator Salvation (2009) John Connor meets Kyle during his teen years. The scar on his face occurred afterwards by a terminator. In this one it opens with a younger Kyle about 7 or 8 years old and he already has the scar when they meet. Either they goofed up or this is one of millions of alternate realities due to the time traveling.

(at around 34 mins) When the T-1000 is chasing the van, it climbs onto the bonnet of the car and jumps at the van. Despite the fact that nobody is driving it, the car not only maintains a straight course, but visibly accelerates, catching up to the van and shunting it.

In the introduction, Judgment Day is said to have occurred in 1997. However, almost every vehicle seen during the nuke scene (Dodge Charger, Toyota Prius, several SUVs/crossovers) are from the late 2000s - early 2010s.

Each time a pathway from the originating time line is created by time travel, it creates a new universe where events unfold differently. See FAQ.

(at around 29 mins) Although first produced in 1982 the Barrett M82A1 (50cal) rifle used by Sarah Connor (in 1984) is the improved A1 model, which was not introduced until 1986. Sarah also uses a MP5K-PDW Sub-machine gun in 1984, the PDW (personal defense weapon) variant was not developed until 1991.

Each time a pathway from the originating time line is created by time travel, it creates a new universe where events unfold differently. See FAQ.

The last part of the movie takes place in 2017. When it is explained that Genisys is taking over the military, two missiles are shown. The first is Nike Hercules; the last units were deactivated in 1988. The second is Hawk which went out of service in the US in 2002.

(at around 20 mins) In a scene set outside the Griffith Observatory on May 12, 1984, the evil T-800 encounters punks standing by a telescope. The Ford Mustang near the punks appears to be a 1985-86 model. The 1985 Ford Mustangs weren't officially introduced until October 4, 1984.

Each time a pathway from the originating time line is created by time travel, it creates a new universe where events unfold differently. See FAQ.

(at around 27 mins) The Camaro seen parked outside the department store after Sarah backs the armored truck out has wheels from a fourth generation (1993-2002) Pontiac Firebird.

The original film operated under a "Causal Loop", where the time travelers' actions created the situation that caused them to travel back in time. Kyle Reese becomes John Connor's father, and the Terminators remains are used to develop Skynet. This film not only allows time travel to change the past, but gives some characters knowledge of how things originally were and how they have been changed. Skynet, for example, is able to send back more Terminators than they had originally, apparently knowing that previous attempts had failed. Sarah and "Pops" also already know that Reese is John's father, and that he was originally killed fighting the first Terminator shortly after fathering John.

All good examples of the twists of time travel. Which part is the Plot Hole.

(at around 1h 6 mins) John Connor says to his mother "you didn't tell him, did you?" referring to the information that Kyle Reese was his father. John Connor had no way of knowing that Sarah Connor knew that Kyle was his father, at that time (he didn't know about Arnold Schwarzenegger's character).

While escaping in the helicopter, "Pops" ducks when they are being shot at, even though bullets wouldn't bother him.