I have this here for anyone that want to compare and discuss. Also it's for me to refer to later if needed.I can go into more detail, but everyone has there own theories about the Ending: I'll throw mine in, but I'll try to keep it short. If anybody wants me to go into detail I can, but I can do just as much in summary. I want to hear everyones theories and I hope this is the Thread you use, so they can all be hear instead of making a buch of topics. (apologies if this was already done, but most of them were like "this is mine, what do you guys think of it?')

So, here's what I THINK is going on.

Topic 1: Indoctrination

1a. Shepard was some what indoctrinated, from very early even. The child Shepard watched die was not real. The reapers knew Shepard was determined, this was an attempt at breaking him.

1b. The dreams he had were effects of indoctrination as well, with the one he has right before London foreshadowing his death, again attempting to demoralize him.

1c. Shepard was resistent to becoming fully indoctrinated, whether through the Lazarus Project or sheer determination.

Topic 2: Reaper Age Tech

2a. The Reapers are remnants of a past cycle, that became self aware and rebelled. With their awareness came a deserve of self preservation

2b. The Citadel's main purpose is to monitor all the races on board, this determines what races are sentient enough to be targeted during a cycles purge.

2c. The Crucible was created by the same ones that made the Reapers, as a fail safe for them. The Reapers never knew of this.

Topic 3: The Ending

3a. When Shepard reached the Citadel the Reapers knew they could ether strike a deal or perish.

3b. The God-child is again the Reapers talking to Shepard, explaining why he looked like the Child from the beginning.

3c. The 3 Final choices represent the terms of a treaty. Left: Shepard have the Reapers leave, letting both sides live. Middle: Rather then fighting, both sides agree to an alliance. Creating a new hybrid race. Right: "F*** you guys, you're assholes," he uses the crucible killing all synthetic life as it was designed.

Topic 4: The Big Picture

4a. The Reapers were created long ago, as weapons. But they became too aware and knew that their power could end all life as they know it.

4b. They remained as well as all their tech as a way to police the galaxy to stop a cycle's potential to end "all" life.

4c. The Protheans are a prime example of this process; they enslaved all other races for the empire. This is why the Reapers came.

After Sorting through all this, it's what makes the most sense to me and explains a lot. Other people will find different things and this one is no way iron-clad. Still, it brought enjoyment when I came to this. Other wise I think the ending sucks, which is what the rumored "Truth" dlc may do. Not change the ending. It's all there just not explained well. Post yours below I'd love to hear them.