Yes, yet another Axis victory. I just realized at one point that I hadn't made my own version of this popular(est?) scenario yet. How can I even call myself an alternate history fan after that?
So what's going on ITTL. Although there were proposals to implement Generalplan Ost on a full scale, it was decided to suspend its implementation due to the impracticality of the plan (which doesn't mean that "untermenschen" are allright - they aren't. While not a direct murder, an industrial slavery for many Slavs is definitely not a very pleasing thing). Most of the ethnic cleansing has taken place in the territory of former Poland and, oddly enough, the former French territories. Although the nature of the purges is different - the French are simply being massively deported to France, while the Poles, in addition to deportation to the General-Governate, face much grimer prospects.
The need to manage such a vast territory as the former European part of the Soviet Union forces the Germans to make certain concessions. More often than not the policy towards the local population depends on the personality of the administrator of the region, practical needs and other things. It is quite common to suddenly "discover Aryan roots" among those locals who have enough funds to ehm.. acquire their Germanized status (Nazi racial theory adapted to this practice, stating that many Slavs are probably secretly of Aryan origin). This practice is especially common in the General-Governate, where people just want to survive so they agree to be "Germans".
Despite the shared name, which implies a certain uniformity of the administrative structure, each Reichskommissariat is governed in its own way. The ethnically diverse commissariats are governed by a "divide and conquer" policy, giving privileges to some groups over others while maintaining German dominance. This approach is used the most in the Ostland and the Caucasus, where a complex ethnic hierarchy has been estabilished as a result. Usually it looks like this: "Aryans" > local minorities (Chechens, Ossetians, Estonians, Tatars) > Slavs > Jews and other "undesirables". However, there are exceptions - in the Caucasus, for example, Cossacks have high privileges, whose status is much higher than local Russians or Ukrainians. In addition, the Cossacks posses a certain kind of autonomy - they have two autonomous regions in the Caucasus and one in Ukraine. Also in Belarus (Ostland) the local administration treats collaborators much more favorably, widely using their services.
If you look closely, you will notice that many of the administrative borders of the Reichskommissariat regions have been inherited from the Soviet Union. This is not the only thing that has been inherited. An institution of collective farms was preserved to establish a system of colonial exploitation, although the introduction of private property is not unheard of. Also, despite the anti-communist propaganda, many former low-key functionaries of the Communist Party retained their positions due to the lack of qualified German administrators.
A full-scale colonization of the east never happened, with the exception of the former Poland (success in which was achieved largely due to mass deportations, murders and such). The main form of colonization in, for example, Ukraine is the generous allocation of huge plots of land to retired German soldiers and officers, who as a result create something like modern Antebellum South-style plantations, forcing the local population to serve as basically slaves. The only "islands" of ethnically German territories are Crimea (now Gothland) and Volgaland (populated by Volga Germans, whose repatriation was one of the German conditions for a truce with the USSR).
Neverthless, as a result of the creation of autonomous entities like Georgia or Tatarstan, the remaining territory of the Reichskommissariat Muscowy is predominantly mono-ethnic Russian. As a result, the practice of collaborationism is widespread in Muscovy (expect several local autonomies like OTL Lokot). At the same time, as part of the project to destroy Russia as an idea so it will never pose any kind of threat to German interests, the development of local identities as opposed to the all-Russian one is encouraged (so not Russians in Arkhangelsk but Pomors, not Russians in Moscow but Muscovites, etc), the process of which in its form resembles Soviet "korenizatsia", although with less success.
Ukraine is in a similar situation when speaking of collaboration, but a bit different one - the annexation of ethnically Russian territories allows nazis to encourage tensions between the two groups while maintaining German direct control. Similar to what is happening in Muscowy, there is also an encouragement of local identities (Volhynians, Sieverians, Zaporozhians, etc).
Still Ukraine remains the most exploited Reichskommisariat. Although attempts at colonization failed, the "preparations" for it were quite bloody for Ukrainians (a series of artificial famines that in terms of victims surpassed the Holodomor of the 30s).
I'm not sure if there is anything else worth taking note of. Well, there is Italy which is not undergoing any sort of split with Germany, remaining an ally to it (not an equal one). Turkey managed to grab some Soviet territories (Batumi and Nakhichevan) but never joined the Axis and is currently trying to maintain neutrality.