Mass Effect 3: Extended Cut changes [SPOILER]

• It is explained how your squad end up back on the Normandy. They get injured by a tank explosion caused by Harbinger. Shepard calls the Normandy for evac and gets his squad on the ship.
• There is an extra scene where Hackett gets reports on Shepard making it to the Citadel.
• All the choices at the end are explained in more depth, and you can question the Catalyst's identity, as well as ask who his creators were (he doesn't tell you).
• When the final choice is made, Hackett warns everyone that the Crucible is activated, and recommends that all the ships in the area evacuate. Joker initially hesitates, but eventually follows orders and leaves the battle through FTL jump.
• There is an extra scene on Earth involving Major Coats.
• There are also extra scenes showing the battles on Thessia and Tuchanka coming to an end.
• Depending on the choice you made, EDI may or may not be in the epilogue scene.
• It is explained that the relays are NOT destroyed, but are very heavily damaged.
• The Normandy crash-lands, but is repaired, and is shown flying off at the end.
• If you have high enough readiness, there is a scene in the Normandy, showing your LI (if you had one) putting a plaque up on the wall with Shepard's name on it.
• There are several still shots at the end, showing some of your squad mates and implying what they did after the events of the end game.
• There is a whole new ending included, available if you either reject all the choices, or shoot the Catalyst.