More random facts! And a quadruple post! (Spoilers)
Ambassador Udina's first name is Donnel.
The squad in ME2 is twice the size of the squad in ME1. 6 vs 12. (Including both Morinth AND Samara)
Tali's outfit changes dramatically from game to game. Look closer. Her helmet is slightly larger, and some other stuff on her head and neck.
The list of the Normandy SR2's crew is as follows:
Commander Shepard - Commanding Officer
Miranda Lawson - Executive Officer
Jeff "Joker" Moreau - Helmsman
Garrus Vakarian - Gunnery Officer
Tali'Zorah vas Normandy - Chief Engineer
Doctor Chakwas - Chief Medical Officer
Mordin Solus - Science Officer
Jacob Taylor - Armory Chief
Kelly Chambers - Yeoman
Rupert Gardner - Mess Sergeant
Gabriella Daniels - Propulsion Engineer
Kenneth Donnelly - Power Engineer
Crewman Patel - Unspecified/Nonrate
Crewman Rolston - Unspecified/Nonrate
Crewman Goldstein - Unspecified/Nonrate
Crewman Hawthorne - Unspecified/Nonrate
Crewman Hadley - Unspecified/Nonrate
Crewman Matthews - Unspecified/Nonrate
EDI - Artificial Intelligence
Unidentified Security Officer - Unspecified (seen guarding Legion in the AI Core before it is reactivated)
There are a few series that describe what happened inbetween the two games. They are called Mass Effect: Revelation, Mass Effect: Ascension, and Mass Effect: Redemption.
Tali'Zorah gets 3 name changes throughout the game.
Legion has 1183 geth programs within it. During its loyalty mission, it says that 573 units voted to repurpose the virus, and 571 voted to destroy the heretics. This is 39 less than 1183, 1144. It could be that the remaining 39 units are still building a consensus, not participating, or even abstaining.
The event shown by Legion, where it plays a recording of when a geth asks if it has a soul, is also referenced by Tali in the first game.
It is possible to skip some squad member's recruitments. This can make Legion be the only geth seen in the game.
When Legion is asked about the fate of the heretics, it says I instead of We, contributing to the fact that it is learning individualism.
If you stand still in the AI core for a while, Legion will begin to do the robot. It will also do this on missions.
Bringing Legion with some squadmates (especially Tali) will result in extra dialogue.
This one is not from a website, I found this. I was walking around on the Citadel with Garrus and Tali as squad mates. Garrus randomly says "Remember when you used to tell us about your life on the flotilla?" and then I think he says something to insult her or something and she ends up saying "I've got a shotgun..."
Legion originally was to be acquired before the reaper IFF. Some dialogue can be heard if it is brought along for the mission to recruit Jack in a moved save file.
Grunt does not use shields. He only uses armor and health. He is unaffected by the sun on Haestrom.
Jack uses some combat yells that were from the original game.
Ardat Yakshi become smarter, more powerful, and more deadly after each coupling.
After the suicide mission, if Morinth is in your crew, and if you are dumb enough, you can romance Morinth. Shortly before finishing the sex scene, you will die and get the Game Over message.
Kelly notices a change in "Samara's" behavior, if you have Morinth instead.
Morinth normally talks in Samara's voice outside of the Normandy. However, there is a node on Tuchanka during the mission to loyalize Mordin where she talks in her own voice.
Sometimes, on the Normandy, Morinth will wear her original black clothing.
Ardat Yakshi are likely based off of vampires. They have much in common, and the ship that smuggled Morinth to Omega, the Demeter, is the same name of the ship that smuggled Dracula to England.
I didn't believe this when I saw it, but Thane is a romantic interest in ME2.
An advertisement in the Citadel refers to Thane as "Sere Krios" if he is in your squad.
Samara translates to "guardian"
If you choose to romance anyone, Mordin will give you some..... entertaining tips and equipment.
Mordin is my favorite character.
Mordin's rule of experimentation: No experiments on species capable of Calculus.
Mordin will cure Garrus or Grunt of the plague if you bring them into the quarantine zone.
Mordin claims to have killed people with guns, knives, drugs, tech attacks and even farming equipment.
If Miranda is romanced, her sex scene is in the elevator, not the captain's cabin.
Miranda means "She who must be admired" in Latin.
The Illusive Man has cybernetic/artificial eyes. The only characters to reference this are Joker and Jacob.
Samara, Grunt, and Zaeed can die outside of the suicide mission. I am not sure how grunt dies, but you can kill Samara in her loyalization mission, and you can leave Zaeed to die in the flames on his loyalization mission.
Chakwas, is an anagram, or scrambled word, of hacksaw.
The Collector General originally tried to recover Shepard's body with Shadow Broker agents, but was foiled by Cerberus.
The very end of the game where the Reaper fleet is seen, they are reactivating.
Harbinger sometimes makes comments on the species of current squad members that Shepard has.
Harbinger controls the collectors in the same way that Sovereign controlled Saren - Implants.
Kelly is a potential romance. She does not grant the "Paramour" achievement, however.
Squad members that work for escorting the rescued are Mordin, Grunt, Jacob, Jack, Samara, Zaeed, and Thane. If they are unloyal, they will die but rescued will live. If you choose wrong, rescued and member will die. If Mordin and Thane are used, both crew and member will survive regardless of loyalty. (I don't think it is possible to lose either one's loyalty, unless you don't do their missions.)
You can buy upgrades and do Legion's loyalty mission before going on the suicide mission and still be able to save Kelly and the crew. Exacly what I did on my first playthrough. (You cannot land or do anything else if you choose to do Legion's mission before going through the relay.)
Found this myself: If Kelly is rescued from the suicide mission, she recalls her imprisonment in the way Thane often recalls his things, with the flashing, bright screen, and the kind of mumbling.
There are several historical races listed, probably the ones exterminated by the reapers before the protheans, listed as the Arthenn, Inusannon, Thoi'han, and Zeioph. The Thoi'han and Inusannon existed at the same time, 100,000 years ago. The Arthenn existed 300,000 years ago. The Zeioph probably existed long before them.
In ME1, there is an anomaly where you find the skull of an unknown creature while exploring a planet.
The big bug thing that drops Klixen in Grunt's Rite of Passage is called a Harvester. They were intended to be in the first game and only be killable by the Mako, like the Thresher Maws.
2-3 Thresher Maws are normally found on a single planet.
Cerberus caused the massacre of Akuze.
Locations of Thresher Maws in both games are as follows: (Note, only ME2 Thresher Maw is on Tuchanka.)
I only encountered one of them in the first game, lured in by a false distress signal, which eventually led me to find Cpl. Toombs and learn about the massacre of Akuze.
Antibaar
Chohe
Edolus
Nepheron
Nonuel
Presrop
Trebin
Xawin
Tuchanka[2]
After completing Grunt's Loyalty mission, if the Thresher is defeated, EDI over the com will tell Shepard that defeating the Thresher Maw has generated several breeding requests for Grunt and one for Shepard (From krogan females)
Rachni songs can be heard on Aeia (a word with no consenants) during Jacob's loyalty mission. O.o!?
Krogan have four testicles. Normally they get transplants, thinking it will help against the genophage.