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 Hathor turns Jack into her first new Jaffa, you can see the line between his chest and the prosthetic that gives him the Jaffa "pouch".
Revealing mistake: When Carter is looking up Hathor on the Internet, the address bar says that the web page is on the C drive of the computer rather than a web URL.
Singularity - S1-E15
Revealing mistake: At the end of the opening credits, they approach a group of three dead bodies to tag them. The second body we see, wearing a light grey shirt, moves its head a little as they are passing the first body. (00:06:00)
Singularity - S1-E15
Plot hole: After Cassandra has her first "heart attack" you see her in her room. Why isn't there one of those heartbeat monitors in her room?
Visible crew/equipment: When Daniel is talking to Teal'c in the jail cell, you can see a camera light reflected in Daniel's glasses.
Revealing mistake: When Daniel is talking to the leader of the Tolan, you can see the camera light reflected in his glasses.
Continuity mistake: When Omoc is approached in the infirmary, he takes off the oxygen mask. But in some shots, the mask is just pulled down and still around his neck.
Character mistake: At the beginning of the episode, O'Neill refers to the planet as P3X-989. When he awakes as an android, he says "Welcome to PX3-989." The P3X becomes PX3. (00:03:35)
Continuity mistake: When the Jacks are talking to each other right at the end, the camera goes back and forth from looking over each of their shoulders at the other one. If you look closely, the false Jack's earlobe structure changes when we see him from behind.
There But For the Grace of God - S1-E20
Continuity mistake: When Daniel returns to the SGU in the alternate reality and Cathrine shows him the map of where the Goa'uld attacks on Earth are, we can see that there are no attacks in the north of Europe, but when we see a closeup Oslo, Stockholm and Helsinki have suddenly been added. (00:14:10)
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.
There But For the Grace of God - S1-E20
Continuity mistake: When the Goa'uld attack the alternate Earth they dial in so no-one can escape. However in future episodes the Russian Stargate program said that as long as a DHD was hooked up to their gate it would have priority. When the invasion happened they had a gate on the ship hooked to a DHD.
Suggested correction: The Goa'uld are well aware of this. All they would need to do is block the event horizon of their Stargate or disconnect the DHD and any incoming wormhole would default to the gate on Earth instead.
The Serpent's Lair (3) - S2-E1
Continuity mistake: When Daniel is shot by a Jaffa staff weapon, the hole in his jacket is very visible. When Daniel comes out healed from the sarcophagus, it has also mended his jacket, but it's shown in other episodes that it doesn't repair clothing.
Other mistake: Teal'c swipes his security card to open a door. The stripe is facing the wrong way, and he really doesn't even get it in the slot right, but The Light still goes green and he opens the door. It is very obvious. (00:26:10)
Visible crew/equipment: After Simian has revealed to Hammond and everyone else why Linea is known as the Destroyer of Worlds, the alarm soon blares and Hammond races to the Operations room. When he's told about the unauthorized gate activation, the white T-mark is visible on the floor. (00:41:00)
Continuity mistake: You hear "chevron four encoded" but the third chevron lights up.
Visible crew/equipment: After Daniel finally collapses in the supply room Jack hugs and comforts him, then it cuts to Sam telling Hammond about the probe's data, and an actor's T-mark is visible on the floor near the stairs. (00:39:10)
Audio problem: Near the very end, when SG-1 have been captured, Daniel says "it's a good day to die", but the subtitles say that O'Neill says the line.
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.
