It's been a long time since I saw this film and, as I recalled enjoying it, I thought I'd give it a second viewing. I should perhaps add at this point that I have never seen any of the various TV spin-offs such as Stargate SG-1 so I can't make comparisons (in fact I didn't realise there had been so many spin-offs until I looked up "stargate" in Wikipedia).
First, a plot summary (with some spoilers). The film starts in 1928 with a baffling archaeological discovery in Egypt; a huge ring several metres across made of some unknown mineral and carved with a variety of strange symbols. Cut to the present day when the US military has got hold of the ring and is trying to work out what it is for. Cue the recruitment of a geeky academic Daniel Jackson (James Spaader) whose radical theories about ancient Egypt had caused him to be regarded as a joke. He is able to decipher the symbols and activate the ring, which turns out to be a stargate, providing instant access to another planet. There Jackson and a team of soldiers led by Colonel O'Neill (Kurt Russell) discover what appears to be an ancient Egyptian civilisation still thriving, but dominated by a powerful alien who has adopted the identity of the sun-god Ra (Jaye Davidson). They learn that Ra had long before transported the Egyptians from Earth to this planet to mine the rare mineral used to make the stargate. The team find themselves battling with Ra for survival and to protect the Earth.
I must admit I enjoy this kind of story – I am fascinated by the sheer alienness of ancient Egypt (without believing that it must therefore have been created by aliens!). I also like the concept of the stargate, which has featured in so many SF novels that it can be regarded as one of the standard tropes of the SF genre, along with spaceships which can travel faster than light. No-one has any idea how either type of device might practically work but they are too convenient to space opera to ignore, so they are usually passed off with mumbo-jumbo about wormholes and warp drives. Another trope is of course the academic with crazy ideas who everyone laughs at until he proves to be right all along, so this movie ticks lots of comfort boxes.
There are also the less forgivable Hollywood SF tropes, notably that radio works instantly, everywhere. The vast distances and timescales of the galaxy (let alone the universe) are far too inconvenient for Hollywood to bother with, so they just ignore them. In more advanced scenarios they apply some more mumbo-jumbo about tachyons, ansibles or dirac transmitters, but in Stargate they don't have such fig-leaves, just ordinary steam-age radio. This doesn't deter them from taking this trope to the extreme, with a robotic probe sent trundling through the newly-opened stargate instantly sending back a radio message via a cute little foot-wide dish antenna from a location which the scientists are able to work out is on the other side of the universe. Umm, guys, you do know how long it would take for a radio message to arrive from the other side of the universe (assuming it had sides, of course)? About 13 billion years….which is even longer than the combined running time of all of the Stargate spin-offs!
Having poked some fun at it, I have to admit that I still like this film. I admired the dramatic alien spaceship and the way it used a pyramid as a parking bollard, and was intrigued by the androgynous Ra – I still wasn't certain whether Jaye Davidson was male or female until I looked him up. There are some engaging characters among the people of the distant planet, supplying both humour and romance. The CGI is dated but adequate. Despite its age, it is well worth watching and still provides far better entertainment than the majority of SFF films. About the only aspect which niggled me this time was the obtrusive and over-dramatic background music constantly sawing away, which does date the film.
A final dose of reality which crossed my mind – the next expedition to the planet had better take a large quantity of vaccines and other medical supplies or the ancient Egyptians would be rapidly wiped out by the accumulation of evolved viruses and other pathogens which we carry around with us.