Revealing mistake: A couple of seconds before the beginning of the opening titles you can see that the eyelids of one of the dead Limvris are moving.
Other mistake: When Dr. Carter is dialing the Asgard, the chevrons spin and lock in, but the screen only shows 7 chevrons locked in. The Asgard required 8 chevrons to reach them.
Other mistake: When the Asgard arrive to save the day they start by beaming out the Goa'ould but Teal'c gets left behind. He should have been beamed out with the rest of them.
Suggested correction: The Asgard know about Teal'c from the season 2 episode "Thor's Chariot". In that episode they upload his DNA profile into the Asgard computers so that he is not beamed away with the other Jaffa in that episode. His profile would have been kept so that he would known in any future contact situations with the Asgard.
This correction seems to have been made without watching the episode (or remembering the episode). The Asgard spoken of are from an alternate reality when they never met Teal'c (and don't have his DNA). One could suggest that alternate reality Carter told them about Teal'c, but there were two of them, and she wouldn't have known alternate reality Teal'c was later killed.
Revealing mistake: When the village canon touches the hot poker to Teal'c's forehead tattoo, the profile view shows that the edge of the applique used by the makeup artist has separated from Chris Judge's face. It apparently was not glued down securely enough, and this is not an isolated incident. It happens quite frequently throughout the entire series.
Other mistake: In the last few minutes of this episode, Carter uses the DHD to dial home. She enters the first chevron, then the "Cannon" dies. And when she proceeds with the dialing,the first chevron is still encoded, and you can hear that she enters seven additional chevrons, which gives an equal of eight chevrons, and then engages the stargate. That would mean they are in another galaxy, referring to S02E15. In that episode they tried to dial the eight-chevron address from SGC but the computer wouldn't accept it. So, it is impossible that they would be in another galaxy.
The Devil You Know (2) - S3-E13
Continuity mistake: When Jack passes out in the pit, he has dirt all over his face before he passes out and no dirt at all in the next shot. (00:24:15)
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.
Plot hole: When the team manage to cause the cavern to form over the buried stargate they send Teal'c through, but shouldn't the cavern be a vacuum? Air doesn't travel through the gate and the stuff caught in the vortex is destroyed, so Teal'c wouldn't need an oxygen mask he'd need a spacesuit. (00:35:00)
Continuity mistake: Daniel's interaction is inconsistent across the episode. Initially, Daniel emerges through the Stargate with no ripples in the event horizon or audible noise. Then he walks down the metal ramp making noise with each footfall. Later in the episode he returns through the Stargate with an audible noise and ripples in the event horizon. He remained "out of phase" for the entire segment of the episode.
Revealing mistake: You can tell the rocks of the cavern are CGI and they're walking in front of a green screen. For example, when everyone goes back to the cavern, with Nick, in one shot the rocks cover part of Teal'c's head.
