Since we finished Tefnut, I wanted to talk briefly about how I designed the planet, to demonstrate just how much "freedom" was intended, and how much was imparted by your choices.
My initial brief for the Tefnut segment, pulled directly from my notes:
http://i.imgur.com/jRexDg6.jpgYou can see the general set of events that actually happened, but things obviously evolved beyond that. By the third draft, created as you neared finishing the first (starter) planet, it looked like this:
http://i.imgur.com/cImoCut.jpgMuch closer to reality! Obviously some small portions changed, such as relaxing the weapon/armor restrictions, but that is basically what you got.
After that I established the basic "routes" that could be followed, of which two were supposed to be immediately available: helping Celirn, or helping Gotek. What you guys ultimately evolved into a third option, namely siding with the Blue Suns, was actually never intended. The volus doctor you met (that Felon delivered that first message for, at the start) was there not to establish the Blue Suns, but to provide a means of saving the station if/when one of the brothers attempted to destroy it entirely. He was working on an engine running off the Distilled eezo you found that was capable of such things, after all!
But the plan you guys established forced to adapt on the fly. The Celirn v Gotek dynamic was already established, and making the Blue Suns a viable third option wasn't difficult. Events like finding the slave girls on your way through were planned then as well, to make it a greyer choice-- even if you guys surprised again, and went for the triple cross.
All of this made Commander Veier a larger character than was ever intended, as was Felon. On the flipside, characters intended to be major players were cut down as you avoided/missed them-- namely the volus scientist, Maximus (the turian Devin played cards with), and Riyo Lait, the drell you found dead. Riyo especially had a full backstory, being a nuclear scientist trained to work on Kahje's fusion reactors. Celirn would have been trying to force his compliance via solipsism torture, and he would have advocated killing both brothers before leaving the station of freed.
This mix of my plans and your decisions altered many of the smaller scenes, such as the meeting with the Shadow Broker agent, the acquisition of Naeir, etc. Major setpieces did survive, however-- such as Faskan's ambush (planned since the beginning of the game) and the attempt by one of the brothers to destroy the station entirely.
All in all I'd say Tefnut turned out to match my plans about 40% of the time, while player action accounted for the other 60%!