I've been trying to get OBS to work for my desktop recording (for the dev series) so I can ditch the piece of shit known as camtasia, and finally reliably record desktop audio in addition to my mic. I'd just use fraps, but the desktop composition is always disabled from the programs I use. Unfortunately, despite OBS claiming to support vegas it has yet to be able to encode a video recorded by that program. So, I don't think the developer series is going to cover audio editing. No loss, I guess; no one really does audio editing these days and probably wouldn't be interested.
Speaking of audio editing, I am probably going to pick up on that sooner than later. I'm aiming for every single impact and weapon type to have a set of unique sounds, and there will be unique sounds for every explosion type, too, of course. Only Xy had engine effects in Salvation, and while they aren't really necessary for this project, I'll probably make/steal some more for the other races. I expect around 2-3 thousand new files will be created for this project.
For music, I have a lot of options that weren't available in Salvation. I have assembled hundreds of tracks for consideration out of my 1.5tb of music, and I guarantee most of them you will not have heard before. While most mods and videos in games are content to copy paste trailer music or E.S. Posthumus, I go through considerable lengths to avoid using mainstream music as much as possible. I was talking to one guy about getting his vocalist to help make a credits track but somehow I think that's not going to happen.
As I detailed in that video, the graphics in Retribution are basically entirely new at this point. I'm aiming for a mix of anime and cinematic style, and those who have seen the test footage so far all agree that it is a tremendous improvement over the previous project. I'm not content with improvement, though. I will continue to push the limits of my abilities and the limits of sins until the very end.

Obviously, accurate scales are impossible in Sins. From the 200 meter fighters to the gas giant-sized battlestations to the Fear and Pride, real-world depictions just won't happen. However, a lot of scales in relativity in Salvation were kind of screwed up. I went through the effort of rescaling a lot of assets during the process of revising them, so they are more accurate to each other in terms of canon. I also upscaled the fighters a bit anyways, so they should be easier to see in fights. There are now Corvettes as well, and many ships (like the Bishop and Leviathan) who had inactivate guns in Salvation due to the weapon limits now have their fully functional armaments.
Beyond sins, the biggest thing this project is getting is actual character representation. I'll be able to graphically and vocally represent some major faces and the world in full to-scale glory. This will be done through the UDK which, of course, I need to learn to make it happen. Again, as some individuals are aware, I've already made progress in that regard.
This area is where things get a bit more complicated. I can, without a doubt, given time, complete the sins portion of this project. The groundwork is laid out; all I need are ship models. That's it. Ship models are very tough because I am incompetent. But it's a matter of time. The UDK is more of a gamble. My learning disabilities, anxiety, and difficulty in focusing make something this complex troublesome. But it's not impossible, and I swore to do it.

The project has been sleeping for close to a month now as I recover. My CTS is a real annoyance and I often just don't feel like doing anything. Because of this, I doubt I will make any major trailers in 2013. Not unless things really pick up soon. But what I am considering doing is making a very short teaser of my particles.
I will tell you what will be the absolute most difficult part of this project content-wise. I intend to make two of the major battles in the UDK. The limits of sins impede these special fights far too much, so I'll be custom animating them and everything. I know it is possible, and within my ability to do. The hard part about it will be not losing hope and giving up before I even try it. That is my greatest weakness. I cannot commit to something and I cannot stick to it to the end.
What kind of developer video content are you interested in?