Revealing mistake: When Teal'c and O'Neill are passing by Jupiter (after the failed missile burn), you can see a reflection in the background window of the cockpit. But the reflection is not the backside of their helmets, but instead is the front sides matted on to give the minor illusion of a reflection. (00:19:20)
There But For the Grace of God - S1-E20
Other mistake: When attempting to dial out about 26 minutes into episode, the Earth gate point of origin symbol locks (indicating that all the symbols are finished encoding). But then "chevron 2 encoded" is announced.
Plot hole: When the team manage to create the cavern with the buried stargate they send Teal'c through to drill his way out, but wouldn't it be safer (and significantly faster) to fire a missile or two through and blast their way out? They have no idea how deep the stargate is buried, or under what type of rock, so sending Teal'c with only four hours of air seems suicidal. (00:35:00)
Suggested correction: Except that sending a missile through would only cause the rocks to cave in onto the Stargate again and could possibly make it impossible to reopen the Stargate. If they could reopen it, they would just end up creating the same cavern. Not to mention the fact the danger to life on the planet if a missile did make it through and ends up exploding on the surface.
Except that if the gate is active, anything falling down on it would be destroyed, so if anything you would still end up with a cavern if material soil bound together as it was falling towards the gate, OR you would end up with a crater which would be Teal'c's objective.
It's not about the rocks being destroyed. It's about if the Stargate ends up shutting down and the rocks creating an iris, making it impossible to establish a wormhole.
Other mistake: In one scene, someone over a P.A. says something like "The mountain is now on emergency power and life support." but the subtitles say M.A.L.P (the probe they send through the gate) instead of mountain.
Summit (1) - S5-E15
Plot hole: During the briefing at the Tok'ra base about the deadly symbiotic poison, Ren'al says that dying symbiotes release their own toxin which is just as deadly to the hosts. Yet in other episodes when a symbiote dies in the host's body, the host doesn't die, even without medical treatment. For example, the whole infected town of Steveston is just fine when all the symbiotes are killed (s06e05).
Other mistake: In several episodes throughout the series, SG-1 is coming through a planet's Stargate but there's no sign of a MALP, even when it should be in the shot. SGC wouldn't send a team through without sending a MALP first (not only to check for a DHD, but survey the land, check for habitability, etc). And if the idea is "well, maybe they have a recovery unit go fetch it before SG-1 goes through", then why would the MALP be present in all the other episodes?
Brief Candle - S1-E9
Other mistake: Jack made it quite clear that he was 40 years old when talking to Kynthia, so if his birthday was in '52, that would put him at 45, instead of 40 years old.
Factual error: In several episodes, there are mentions of travelling many million light years, even though they're still in our own galaxy. However, the Milky Way is estimated to be around 100,000 light years in diameter.
Other mistake: At the end, Anubis/Vaselov is sent to KS7-535 and we see a shot of the gate being partially buried in snow and Anubis frozen. However, the wormhole should have cleared all the snow in its path when it established, meaning it wouldn't be buried in the snow as seen.
Character mistake: When Hammond and Carter come out of the base, Hammond is told he's been gone 22 hours. Hammond says he's only been gone about 20 minutes. To which Carter says, due to time dilation, time is moving an average of 600% slower and that telling O'Neill to wait 5 minutes would be 6 hours or more. However, 600% is just another way of saying "6 times" and time is slower by about 66 times, so she should have said an average of 6,000%. 5 minutes being 6 hours would be 72 times slower.
Character mistake: In the first scene in the coffee shop, Pete suggests going to the Zoo and Sam tells him there is no zoo in Colorado Springs. Colorado Springs does have a zoo, that was founded in 1926 and has operated continuously since. It is less than 3 miles from the city center and Sam both attended The Air Force Academy, and has lived in the city for at least seven years, so it is inconceivable she wouldn't know it exists. Also her answer appears genuine and not intended to deflect Pete's invitation by lying. (00:04:30)
Other mistake: Teal'c says "Mother ships do not possess cloaking capabilities" But Apophis in season 4 had cloaked Mother ships.
Continuity mistake: When Carter gets stuck in the elevator, she's on level 22. Every time the level changed, you can hear a beeping noise and there's no noise after we see 22. But from outside, the doors say 28. It wasn't a cut away shot either.
Continuity mistake: When the sarcophagus explodes, the blast door they escape through has no card reader. Once they stand up it's there. (00:37:55)
Revealing mistake: When Carter says "It will just take a few minutes to initialize" at the super-gate and presses the screen on her hand you can see for a brief second that it is a video recording since the options for play, pause and stop show in the options bar on the screen. (00:36:30)
Deliberate mistake: In the scene when the timer exceeds 38 minutes, said timer is displayed in big digits on a computer screen. There is a shot of General Hammond with the Stargate in the background. There is a pane of glass between the General and the Stargate. In the shot, General Hammond turns and looks at the gate, and then the camera's focus changes from the General to the Stargate itself. In doing so, a reflection of the timer in the pane of glass is also brought into focus. However the timer is displayed correctly when it should be flipped left to right as all text is when it is reflected in either a pane of glass or a mirror. On the DVD, the writers revealed that this was done on purpose so that the viewer would have a concept of the time running out even when the timer wasn't in shot. (00:17:30)
Visible crew/equipment: Just after Jack says "Whoa, did you guys hear that?" a person in yellow is visible in the background (either in the building, or as a reflection in the window). (00:01:30)
Continuity mistake: During the surgery, when they attempt to remove the Goa'uld, they start a timer. The timer starts at 00:00:00, then it blacks out (obviously, you don't want to be bored by major neck-surgery), and then the timer is at 01:19:49. However, seconds later (after Carter and Daniel's conversation), look at the timer in the background, it reads 00:23:46. (00:32:35 - 00:33:10)
Revealing mistake: In the scene where Thor beams onto Loki's ship, as he stands there you see him turn his head. However, if you watch his reflection in the window behind him, his reflection stays facing forwards.
Continuity mistake: In a scene where Sergeant Walter Harriman tells General Hammond that SG-1 is ok, but Dr. Friesen is dead, Sergeant Walter Harriman is wearing the uniform of Major Davis (you can see "Norman Davis" written on left side of his chest). [His name was originally Norman Davis. At one point, Hammond refers to him as "Airman". This was misinterpreted as him being called "Harriman." Then, in the episode 2010, O'Neill calls him Walter. Thus, his name changed from Norman Davis to Walter Harriman. Still a mistake, but that's why.] (00:30:15)
