I beat the game 2x more last night; if you check your load options, there should be 1 called "restart citadel mission" or something close to that. I explored dialogue options and more importantly, did all 3 choices. 1st time through I didn't fully understand what the kid was telling me, but now that I heard it again I get the message. Initially I was unhappy that I choose Synthesis for my real file, but now that I had the chance to hear his explanations again, I'm happy with it. He said it's the final evolution of life and will make the cycle system unnecessary and stop it. This seems like the truest "peace" and I'm happy with that.
Say what you will about the ending, but the music and the camera shots (cinematography, I guess is the word?) are EXCELLENT
From the moment where you run for the beam with the explosions all around, get back up and limp towards the beam, walk through the corpses on the Citadel, up the ramp, and finally, into the room with Anderson and Illusive man, up the platform to the area with the 3 choices... those shots and the music are BEAUTIFUL. Play it again and appreciate everything but the dialog.
I'm OK with most of the ending, more than most people, I think. Everything is fine until they show the Normandy flying away and crash landing on that jungle planet. This I just can't understand, how are they not back on Earth? Especially since it shows Garrus getting off the ship, that dude was with me in my final squad; I'm pretty sure everyone got wiped out by the Reaper laser.
Still, I really appreciate the music and the cinematography of the final parts. Sends chills down my spine. For anyone that's only beat it once, load up that save; it starts right where you enter the beam.