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.
Plot hole: Huge plot error: Apophis and Clorell (Skara) should not have survived the explosion in Season 2, Episode 1 (when they attack Earth with two ships). In "Family" they explain that Apophis and Clorell survived by escaping through the stargate aboard Clorell's ship moments after Daniel Jackson did the same. However, when Daniel Jackson escapes through it, Apophis and Clorell are not even on the right ship, and there is 1 second left on the C4 timer when Daniel escapes. They actually show Daniel Jackson escape, and then cut to Apophis and Clorell still aboard their ship. So apparently, Apophis was able to "ring" from his ship over to Clorell's ship, make it to the stargate room, dial an address, and escape through the stargate all within literally 1 second. Is this guy related to The Flash?
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.
Factual error: The escort for Colonel O'Neill is wearing both Major and Staff Sergeant rank insignia. Probably what the writers thought was a "Sergeant Major", which does not exist in the Air Force. Major is a commissioned officer, sergeants are non-commissioned officers.
Plot hole: Before the last chevron locks & the wormhole engages, Carter asks "Where's the iris" to which Hammond 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.