Snakepit

What happens when a galaxy full of enslaving creatures that think they're gods comes clashing against a planet full of hypercompetent enslaving people who think they're gods? The answer is Snakepit, by Dark Schtroumpf, as the Goa'uld come head to head with a post-Final War Domination of The Draka.

The entire Stargate universe has been tweaked to make it more realistic, everything from how the Goa'uld's magic/technology shitck would actually affect their worshipers to the now-imperialistic Tollans. In fact, while Earth basically follows Draka canon to the letter, the SG-1 universe is a sort of Gritty Reboot.

The story can be found here. There's also a sequel, Stars of Iron, in progress^[when?]. The sequel is also posted (with active discussion) on both AlternateHistory.com here and on Spacebattles.com.com here. There are also two vignette interludes that take place between the two stories.

Tropes used in Snakepit include:

Aliens Speaking English: Averted. No one who isn't from Earth speaks English: the Goa'uld language is the galaxy's lingua franca, and even human cultures like the Tollan have their own tongue. Luckily, the Draka learn quickly.
Alternate Universe: Fairly obviously. There are two separate levels of Alternate Universe going on: for the first level, Earth's history, which is entirely alternate history, then there is how the SG-1 universe is affected.
Asshole Victim: Bar'shan, eventually.
Badass Bookworm: This universe's version of Daniel Jackson served in the Draka paratroops.
Black and Grey Morality: Frequently pushing into Black and Black Morality.
Came Back Wrong: The Goa'uld sarcophagus, which in canon caused megalomania in humans with repeated use, turns out to have an...interesting effect on drakensis, as Decurion Rayner finds out.
Complete Monster: Invoked by Bar'shan, after he captures, tortures and rapes Decurion Rayner.
Crowning Moment of Awesome: Invoked when a Draka tank kills a Kull warrior with a 120mm tank round straight to the chest.
- It's also invoked during Tetrarch Arminius Vohn's capture of an entire Goa'uld bomber squadron.
Crowning Moment of Heartwarming: invoked when Cenor and Natylis have a mutual comfort session with Decurion Rayner in the hot springs.
Cruel Mercy: What Chang-Mu does to the villagers who abandoned her instead of outright killing them.
Darker and Edgier: This story lives in this trope.
Disproportionate Retribution: When Bar'shan captures Decurion Rayner, the Draka kidnap him, kill all of his men, pillage his base (before nuking it), and use him for medical experiments.
Drill Sergeant Nasty: Drill Sergeant Hartmann in "Rebirth of the Janissaries."
Dropped An Ancient Superweapon On Them: The Replicators.
Even the Girls Want Her: Gwendolyn Ingolfsson unleashes this trope while serving as a liason on a Tollan ship.
Evil Versus Evil: The Domination vs. the Goa'uld.
Expy/NoCelebritiesWereHarmed: An American computer expert named Stuart Gates is sighted, having accepted Draka citizenship. He likes to sing his own theme song and be told he's "the man" by his serf concubine.
Happiness in Slavery: The Domination's serfs, after they're genetically altered.
Heel Face Turn: Decurion Rayner comes to view enslavement of humans as evil, although she remains loyal to the Draka because they're her people.
Hotter and Sexier: Remember how the pilot of Stargate SG-1 had full-frontal nudity? Imagine the whole show had been like that, only a lot more so.
Human Aliens: The Drakensis and their Servus slaves, obviously. The Goa'uld, on the other hand, are just aliens in human bodies.
Idiot Ball: Zig-Zagging Trope, both universes had factions who regularly jiggled with it in their backstory. The actual story's characters are usually competent, but more often than not their enemies are better.
Ineffectual Sympathetic Villain: Karl'ac, the Goa'uld whose desperation ploy unleashed the Draka on the galaxy, with a side order of Butt Monkey.
Melee a Trois: The Draka and Tollans vs. Anubis and his minions/allies vs. the other System Lords. Stars of Iron introduces additional factions in the form of the Tok'Ra and the crew of the New America.
No Transhumanism Allowed: played straight with the Tollan, averted with the Draka, and subverted with the Gou'ald who are improving their slaves, but not themselves.
Nuke'Em: The Draka's reaction to an infiltrating energy lifeform invading their version of the SGC? Stuff a nuke in the gigaton range through the gate.
Pet the Dog: De Polignac's kind treatment of the Tollan captive they rescued.
Put on a Bus: The New America after being transported to a distant star system by Loki, until the sequel.
Shout-Out: Various, including the Jaffa named Bal'dric.
Start of Darkness: Cenor joining in the rape of captive Goa'uld worshipers along with the other recruits in "The New Janissaries."
Super Soldier: Where to start? The universe is full of them: on the Goa'uld's side there are Anubis' Kulls and Yu's Dragon Guards. On the other side, there are the Draka themselves, due to genetic tinkering.
Superior Species: The Drakensis like to think of themselves in this way. Considering what they're capable of, it's hard to argue with them.
There Is No Kill Like Overkill: This is the Draka's basic outlook on everything, from combat to spaceship design.
The Remnant: "New America," or "The Republic of Samothrace."
Training from Hell: Cenor and other Tollans are put through this by Drill Sergeant Hartmann in the vignette interlude "Rebirth of the Janissaries."
Villain Protagonist: All the Draka characters, obviously, though some more than others. The most highlighted Draka, Anton de Polignac, is introduced capturing an American family, manipu lating the wife into giving up the location of her husband and other members of La Résistance, having her son castrated and taking her daughter as a sex slave.
World of Badass: Earth is this, as it unleashes both the Draka and Samothrace on an unsuspecting galaxy.