BackFire
Blood. It's nature's lube
I just finished the extended cut. I will give a rundown of the changes that I saw. It is extremely late and I'm very tired, so I'm going to be brief.
Spoiler:
The first addition is that the scene in which Harbinger shoots his laser at Shepard and his team is now different. Your squadmates are both injured from a tank landing near them. Shepard calls in the Normandy for evac for your team members. In the playthrough I did I brought Liara with me and she was my love interest. She did not wish to leave Shepard, but he more or less forced her, because she was hurt. After this the scene with the laser nearly killing shepard occurs.The next change is a minor one, instead of Shepard waking up on the Citadel he is shown being shot up from the hole in which the beam originates, he is never passed out. Also there is a small cinematic where Hacket recognizes that someone made it onto the citadel.
After that everything is the same up until the conversation with the catalyst, which differs greatly from the original. You now have the opportunity to ask it more questions about his origin and who created him. You can also challenge him more. Which leads me to the final and biggest change.
There is in essence a fourth ending. You are now able to flat our reject the Catalyst's solutions and refuse to cooperate, saying that you'd rather die free than be forced to make a choice you don't agree with, from a premise you don't agree with. Once you do the Catalyst's voice changes to that of a reaper and says 'so be it, the cycle continues'. And then The Reapers basically win. The ending cinematic takes place many centuries later, and shows a VI of Liara, similar to Vigil on Illos, giving a warning to the future, and saying that the information hidden on this VI will help future cycles defeat the reapers, even though her cycle was destroyed.
Then the credits roll and we are shown the epilogue scene with Buzz Aldrin, but he is replaced with a female alien talking to the child. The female alien says that the information left behind by The Shepart helped them avoid the reaper threat and allowed them to live in peace. I didn't see how the ending plays out if you accept the choices presented, I will do so tomorrow.
