For the purposes of reviewing the Gartegens as a potential Player Character race, I will review each sub-article and examine the impact it would have on roleplayability, and also point out resemblances to other factions in the setting. Our goal with SARP is to enrich the setting with new content, not drown it out.
I will not review this as a conventional tech article, as race submissions are so radically different from those for starships and new weapon systems.
Stage 1: "Gartagen Physiology"
Digitigrade species aren't all that strange, I suppose, although I wonder why you didn't go further and give them non-human skin types or more alien features. Their current physiology is more evocative of Satyrs or the Christianized demons. Rather than any defined aesthetic, they seem to sit somewhere between the Tau, Fremen and Predators (of Ahh-nold movie fame). Having a clearer aesthetic when defining non-human races should be a big consideration, or they won't really be interesting or memorable.
Since you attempted to plagiarize the game in the past, you should take another look at Mass Effect. Each and every race in that setting is unique and memorable on its own, despite being entirely homebrewed by BioWare and not being directly based on any of our current alien mythos (i.e.: Grays, anything from Star Trek, the Wars, etc...).
In regards to performance... is there any environmental reason for the bones being denser? If they have more endurance than baseline humans, why do they have lower thresholds for pain?
And a final question. Isn't face to face lovemaking more difficult for digitigrades?
Stage 2: "Gartagen Culture and Psyche"
So politically, they're an oppressive police state that blankets mental indoctrination in 'honor code'? A lot of races seem to have this level of loyalty naturally, but you have the sand to actually say that this is done. This is pretty interesting, but may cause conflicts with other writings that you have.
Traditionally, societies that indoctrinate their members in such a profound manner do not foster creative thought or new ideologies very well. Thus, the statement that Gartagens are open-minded would be somewhat invalid, since they're indoctrinated to believe in the state no matter what, in spite of the good or ill that it does. They believe that the state is infallible and must be followed even if their conscience screams the opposite, because the mindset of the 'state first' overides those of morality.
Childhood indoctrination (especially if you have some level of prowess in psychological techniques) is a powerful thing.
No personal computers (thus no free access to information) and no digital entertainment. Fair enough. Information technology is around the 1960's, then, or being hoarded by the government? The latter seems more likely, since you have powered armor and pre-FTL flight. It sounds a bit backwards, but since this is clearly a Statist regime, the citizens would hardly object.
Religion is a bit bland, to be honest. Part of the fun of saying that your race has a religion or several is writing about the ones that it has.
I also share SSharp's concerns on the emotions, although mine are more directed at the 'human but not but also more human than human' theme that I've been seeing with the grand majority of new player races. I'm a bit guilty of it, since I was the second to last PC race/faction to be approved, but you've made it rather complicated. Most of their expression is conveyed though scent and body language, the subtlety of which is lost on a majority of human beings. And then there's the issue of emotions.
http://www.youtube.com/watch?v=xACbVe7o9Rs This is a lot of emotion. Notice how it's drowned out, and really fails to affect you?
http://www.youtube.com/watch?v=a_saUN4j7Gw Compared with this scene, where the characters don't express much more emotion than a big of pain and fear, but you can read so much more into it. Emotional subtlety is perhaps the only good way of conveying emotional depth.
From what I've seen, the Gartagens can only really feel extremes of emotion, which really has no proper way of being roleplayed. And again, looking at many good sci-fi settings... you're remark that alien races are rarely more emotional than humans, because most writers haven't the foggiest clue on how to write that without making a bipolar, schizophrenic mess. Psychological differences should be in the patterning (the way they think, they way they feel), not the scaling (how much they think, how much they feel).
From the remaining sub-sections, I've formed a pretty solid image of the Gartagens. They're rather close-minded, clannish and slavishly obedient to the whims of the state above them, although following a strong ethos in regards to their society. Because most of their behavior is decided by forces outside of themselves (familial bonding, sexual bonding, indoctrination, information restriction) there will probably be very little for a player to do, besides provide the voice to a puppet who is having their strings pulled by another person.
It doesn't seem to be very good material for a PC race, at least at this point. Any characters made would be quite uniform compared to Nepleslians, Yamataians, Lorath or Iromakuanhe... and even engineered soldier species like Nekovalkryja, since their parent nation encourages the creation of a unique identity.
I will post additional reviews in the immediate future.