The dimly lit opening scene set with all the electrical looking stuff is a real world location only slightly dressed up. The Powetech company near Vancouver has a high voltage Resonance Test Set that is frequently used as a filming location because it is a very large space filled with very large exotic equipment.
The second and third shots of Michael Shanks as 'Daniel Jackson' shown in the opening credits (one where he runs into a scene that has the Stargate in the background with a closed iris, and the other a closeup taken from a low angle as he studies something out of view) are both taken from this episode.
The trivia items below may give away important plot points.
Carter says the weapons used to destroy the East coast created 200 megaton blasts. For a bit of perspective: The largest thermonuclear warhead ever detonated on Earth was the Tzar Bomba, a 50 megaton release. An air burst, it created a fireball 5 miles in diameter, a mushroom cloud 40 miles tall (remember, space starts at 62 miles), and destroyed all buildings within 35 miles.
The teleplay is by Robert C. Cooper who later becomes a producer. This story is loaded with plot points that show up through later seasons. It marks the first time the following major points are referred to: 1. alternate/parallel universes; 2. 38 min time limit for keeping the gate open; 3. Mention/use of a Beta site; 4. parallel universes with different team members of SG-1; 5. Teal'c deciding to leave SG-1; 6. Alternate Sam with long hair; 7. SG-1 travel aboard Gou'ald space ship; 8. first time showing the interior of a gou'ald space ship; 9. first time showing the stargate operating on a spaceship; 10. first time showing a mechanism to control a spaceship (although changed in other ships); 11. first to show death gliders; 12. first to show planetary invasion using gou'ald ships; 13. first to reference Sam speeding up dialing process for the Earth gate; 14. first to reference self destruct in response to gou'ald invasion; 15. first time showing Daniel Jackson looking himself up in an alternate dimension/time-line; 16. first time showing SG-1 risking court martial and disobeying a direct order; 17. first time showing gou'ald two-way communication sphere; and 18. first to make explicit reference to Sam and Jack's romance, even if only in an alternate dimension. There are undoubtedly others.