Here goes!
Continuum
Being a SG fan, I enjoyed seeing the whole crew, both new & old, good & bad guys, all brought together for this movie. I also enjoyed the scheme of 'changing time' and 'alternate realities'. The one thing, of time jumping from present to past, (flipping & flopping) made me pay attention to the time line. But, maybe just the reason to watch it again!
Loved the music so much that I listened thru the end of the credits!
Present Day: [The initial one shot walk thru by the director is great and brings the base review alive]
The gang of General O'Neill, Teal'c, Daniel, Sam, Vala, and Col. Cameron Mitchell, are assembled for a ceremony of the Gou'ald extraction of Ba'al. This is form of punishment for crimes he has committed, death to his symbiote.
Jumped To 1939: Just before WW II, the Merchant Marine Vessel, Achilles, transports Star Gate found in Africa to America. Aboard is the Captain who knows it is top secret.
Present Day: The long and boring ceremony is interrupted when people start disappearing. Ba'al breaks out and stabs Gen. O'Neill dead.
Back To Past: Ba'al comes thru the gate in 1939 that is on board the ship, taking it over and killing everyone. He has been working on changing events in time.
Back To Present: The balance of the people & things that were left at the ritual are quickly disappearing. Sam, Daniel, Col. Cam were ordered by Gen. O'Neill, his last words, to get back to Earth. They dial the gate, but arrive at an unfamiliar destination.
SG1 are in a ship frozen in the Artic Circle and race to find escape before they freeze to death. Col. Mitchell blasts a hole to get out, but dislodges the ship and it sinks. Daniel gets frostbite to his leg and elects to stay, not to slow their escape.
Sam and Mitchell walk across miles of ice to find rescue. [The scenery of the Artic is beautiful] Just as they are about to give up, they are met by O'Neill who was out investigating the quake caused by the Star Gate activation. O'Neill is not their O'Neill. He believes Sam is dead astronaut, knows nothing of the Star Gate, has no sense of sarcastic humor (that we love!), is all military in Special Forces.
A submarine pops up thru the ice which they board. They find Daniel, who was picked up shortly after Sam & Mitchell left.
[There is a great editing sequence of the interrogation of the three SG1 members] SG1 knowing the timeline has been changed, wants to correct it, and pleads up the chain of command. But no one will have any of it. They fear that their lives will cease to exist. Landry orders them to be kept apart and not seek out anything to do with the Star Gate. They have to accept living this alternate life.
One Year Later: Alien aircraft arrive on Earth from Ba'al.
Parallel in Space: At this time, Ba'al is now ruler over all the System Lords. Vala (Who is known as Qetesh with a Gou'ald) is his queen, Teal'c is his 1st Prime, and Apothois is killed by him.
Ahh, but he didn't tell Qetesh of this plan. Qetesh (suspicious, ambitious, jealous, greedy & revengeful), kills Ba'al, witnessed by Teal'c. It is now Teal'c's duty, as first prime, to get revenge for Ba'al's death, and Qetesh's goal to kill Teal'c and take over Ba'al's plans to control Earth.
Back To Earth: SG1 fly in squadron to find the Gate at McMurdo Military Base to change time back. The Base with the Gate is destroyed. The planet is being disseminated, country by country. Russia reveals they have a second Star Gate. A dog fight ensues with the alien gliders, and Russia assists.

In Russia at the gate, they meet Teal'c and convince him to work with Earth ("you can free the Jaffa"). Together they gate to Ba'al's 'fail safe' - which is his time machine. Sam works on solving the operation of the machine. After finding a solar flare, enabling a time jump, she dials out as Qetesh warriors arrive and the fighting ensues. Daniel is killed,

Sam is killed,

taking hit after hit, Teal'c is killed,

and with Qetesh standing over him, he drops grenade, "I die free".

At the last moment, Mitchell jumps thru the gate.
1929: Mitchell arrives in 1929 and positioned himself working on the Achilles, just waiting.
1939: Ba'al's expression from confident ruler of all, to being shot by Mitchell (like what the hell?), thwarting Ba'al's plans are priceless.
Back To the Future: Back to the Extraction, as if nothing has happened, Ba'al is having a needle drilled into his forehead to extract the symbiote. All the people we love are alive, the timeline corrected. The boring ceremony is over, O"Neill inquires about lunch, and he's paying!
As they leave the locker room, the image of the picture on Mitchell's door has changed. Which makes you wonder, what else has changed.
Jerseycoconut

Loved it!