I've never looked at it as a cultural difference to be honest, most of the time it feels rather like sloppy writing, as if there were unmentioned jumps in time or something similar.
That's because you are stupidly ignorant about the way these people think and feel...
See what I did in that sentence? I was blunt and very direct about how you perceived the writing. I simply pointed out how you lack the understanding about their way of thinking/feeling, but i did not tell you you were wrong either. You have a western viewpoint, one that I share btw. The first half of the game feels a bit jarring sometimes because of the writing, but their style in communication is just more blunt and to the point.
But if you have the more western mentality: It is possible you feel a bit offended or put down by that statement, that was not my intention and I apologize if you do.
In eastern Europe, you take your shitty feelings and you deal with that on your own time and you do not go about bothering (almost) strangers with those (like a certain girl that just walked in and booted you out of your bed) that kind of feeling-sharing is (at best)for more intimate relations like lovers or family (and even they will probably just tell you to deal with it without whining) It is why the game opens up more in the later stages.
That concludes what little (and probably flawed) understanding I have of Russian/Eastern Europeans.