Revealing: As we know, the watery image of the event horizon is projected onto a blue backdrop. In "Origin" the third episode of season nine, Ger'ak comes through the Stargate and we can see the image of the event horizon, though faint, around and above the Stargate itself and is not confined to normal area for the event horizon. Blatantly visible if you look for it on the airing of the episode on the Sci-Fi network.

Continuity: When Teal'c attacks the blonde Jaffa, the Jaffa has a staff weapon, but the shot changes when Teal'c hits the Jaffa and the staff has disappeared.

Continuity: Season 9, episode 14 "Stronghold": When Bratac has cleared the gate in his alkesh, there is a shot of the gate from nearly side on. There is now a wormhole, despite the SGC dialing it less than a minute before.

Factual error: Before SG-1 switched to P90 PDW's, they carried MP5 submachine guns. They were often shown with a full magazine taped upside down to the one in the weapon, so that to reload, all they have to do is remove the magazine, turn it over and insert the full one. Problem is, real special ops troops are specifically taught in training never to do this. It's far too easy to damage the lips on the spare magazine, rendering it useless. The magazines are designed to be attached side by side, not with one upside down.

Continuity: In Season 8 - Threads, when Sam is talking to Jack in his backyard (barbecue scene), the back door behind her opens and closes between shots.

Continuity: Season 7: Lost City. When they are about to blow up the ancient device at the ruins, Col O Neill sticks a wad of C4 to the wall in the corner, when the shot changes, the explosives have moved approximately 6 inches to the left.

Revealing: Season 10 episode 4 - The Insiders. When Baal is making his escape right before the Symbiont gas is released there are two shots of Baal clones entering into a room. In both shots one of the Baal clones is not Cliff Simon.

Continuity: Season 10 Episode 15: In the scene where Teal'c and his friend are ambushed offworld, he shoots back without first "opening" his staff weapon. After firing back, it is suddenly opened.

Continuity: In the episode "The Shroud," during the scene where Jack is talking to Daniel aboard the Odyssey, there is only 1 star on each of his shirt collars, indicating that he is a Brigadier General, instead of the proper two stars for a Major General, as he does in every other scene of the episode.

Other: Season 8, Episodes 16 & 17 - "Reckoning" The Replicator ship on which Daniel is being held prisoner is supposedly made entirely of Replicator blocks (a fact established in earlier episodes), yet only the walls of the set are made to look that way. The floor, visible repeatedly throughout the episode, is simply a concrete slab painted the same gray color as the block walls.

Continuity: Season 9 Episode 13 "Ripple Effect": When "Desert Camo" SG-1 returns to their dimension through the Stargate, we hear 5 "slurps" indicating someone passing through the gate, however there are only 4 members on the team.

Plot hole: Anytime an SG member starts acting weird or something happens that is "impossible", SGC personnel always act skeptical about it. Considering what they have seen in the course of the show, "that's impossible" should have long ago fallen out of their vocabulary. And while I realize that Sam and Daniel are scientists, they have seen enough examples of incredibly advanced technology that they should be far more open-minded when looking for explanations.

Factual error: Earth's Stargate is dialed up more then once in series 1. Mostly in the first episodes, the passive gate is also shown with a rotating dialer ring when being called. This is not correct. The called gate only illuminates the chevrons. (This is classed as a 'factual' mistake within the show, not a 'continuity' error, and the option to change type has been removed.)

Factual error: Carter claims that the gates shift position because of the expansion of the universe. Gravity sources within a galaxy completely compensate for such expansion. The gates would still experience "stellar drift", which is mentioned earlier in the same episode. Stellar drift occurs because stars orbit the galactic center independently.

Revealing: When Daniel, Jack, and Sam first meet the robed Jaffa in the woods, you can see the camera light in Daniel's glasses.

Revealing: When Apophis' queen goes back into the female Jaffa, it is obvious that the film footage was just played in reverse.

Other: When O'Neill first goes to visit Teal'c in his cell the symbol of Apophis on Teal'c's head is upside down.

Continuity: When Kawalsky is on the operating table, there is a shot of the clock showing 19 minutes after the hour. The next shot is of Carter and Daniel talking, then the shot returns to the surgery and the clock says 23 minutes.

Other: Before the last cevron locks & the wormhole engages, Carter asks "Where's the iris" to which Hammind responds "Someone used a remote, whoever it is has our codes". All well and good, except without the wormhole being active, they wouldn't be able to receive the code.

Revealing: 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".