I had been waiting for some time the release of this game in the "West" (it was released at least one year ago in Russia) and after a couple of quick playthroughs I've got mixed feelings. This is a pretty sophisticated title which is flawed by the lack of proper documentation.
The graphics are outstanding. You really get the feeling of being fighting for the Rodina on the steppes to the south of Kharkov. They got a really good rendition of the land: elevation, vegetation, roads and other elements are modeled with care and great detail. Vehicles really strike to me as particularly well done. Infantry moves like people, although some animations seem to be taken out from some Soviet propaganda film, with soldiers throwing their weapons to the sky when hit by a mortar fragment. The graphics engine is really one of the best I've seen on a tactical wargame. For instance, soldiers graphics become billboards when you're far from them, smoothly transitioning to a lush 3D model when you close on them.
However graphics in a wargame, in my opinion, should cater more to transmit faithful information to the player about what's going on than to get from us an "Oh, shiny!". In this department I find this to be lacking. When you look at the action really close you can see your infantry - especially when defending - doing weird stuff, such as wandering like zombies in the middle of an intense firefight.
The User Interface it's very good, though it suffers from some weird translation - what does exactly mean the order "Hidden Move"? - and a quite whimsical choice of hotkeys, which can be remapped to our liking. Although I've still to master it, I've found it has all kinds of tools for focusing the attention of the player on important events happening on the battlefield. It allows you, for instance, to decide whether the game gets paused when a friendly unit spots an enemy unit, takes losses, etc. One can also get the UI to focus on the unit in question and other options I'm not sure what they're doing because of the translation.
The campaign being portrayed is a really interesting battle - if relatively obscure - http://en.wikipedia.org/wiki/Operation_Star which has been seldom visited in wargaming in general. It also comes with a Quick Battle system, which allows to select the battle place - restricted to the locations modeled with excruciating attention to detail - and to buy the opposing forces. Besides that, it apparently comes - haven't checked it yet - with a fully featured Operation editor. So, in theory, one could make campaigns covering a good proportion of the many battles fought in the Eastern Front during November 1942 and March 1943.
Regarding the simulation I've got mixed feelings. The infantry combat model looks good, but I'm not really sure until I get to observe more battles that it's in the same league as the recently released Combat Mission Normandy. TacAI seems to be quite good, though, and there are plenty of parameters that can be controlled from the UI - such as formation - which allow to nuance the generic commands available (Move, Attack, Defend, Recon, etc.).
Where I find Operation Star really lacking is in the documentation department. There's an ingame tutorial - called "Training Mode" - which is quite inflexible. To make an analogy, it's a bit like someone pulling your ear to make you pay attention to the many - perhaps overwhelming - options available, and the order in which the tutorial "pulls your ear" feels a bit random. There's NO manual explaining with some depth formations, unit orders, etc. and other stuff that would be nice to know about.
I'd certainly recommend this game to people heavily into computer wargaming at the tactical level interested in the Nazi-Soviet struggle, who don't shy away from Real Time gameplay (though pausable and as I said before, you can link pause with events), lack of multiplayer and absence of any real documentation.