Well, that'll teach me to post throwaway comments I think won't be seen.
OK, since I was fairly upbraided for a too-short post, let's throw in a nice big meaty one. One thing I've not seen discussed a whole lot in Papers, Please is the use of screen layout. Since it's a fair part of why the game works, I thought I'd try to throw in a bit of discussion of it. Some minor spoilers below, but not a whole bunch.
So, roughly the screen is divided into two sections, which are themselves divided into two more. (Yeah, I know. The top section has no firm divide, but the wall above the booth neatly divides it up anyway.) The left hand sections are smaller than the right hand sections, and the bottom sections larger than the top.
You can make a good argument that section three is actually two sections, the personal space and the desk space. That's correct, but I'm just going to ignore it for this analysis.
There's a lot of interesting stuff all this layout design produces. Generally, our eyes are going to drift to the largest area available to us, section 4, which is where the main gameplay occurs. The second largest area available to us is section 3, which draws our attention somewhat less and is the second most important area to gameplay. Notice also the position of our stamp and examine tool, way over on the right. Putting them on the left would be more convenient to us, as we need to keep our attention between sections 3 and 4. Being put there is a deliberate inconvenience, one that encourages us to spend our valuable dollars on upgrades.
The thing is, though, that all four sections of the screen will eventually be used in one way or another. The Man in Red shows up in section 1, for example, while terrorist attacks always occur in section 2.
Sectioning the screen off like this serves a few purposes, which work to further both the gameplay and the thematic strengths of the game.
First, as has been widely observed, it works to constrain the player by limiting the amount of space to juggle multiple documents. While section 3 allows a player to take a document 'out of play' to save space, the end result is even more wide mouse swings that chew up valuable time and frustrate the player. Documents easily wind up overlapping and it's common to lose a document in the pile. Thematically, this winds up making the player more willing to be terse with immigrants, trying to reclaim time and ignoring the options available to potentially help people with more difficult cases.
But secondly, it also serves to train the player to ignore the top two sections, even though many of the important events of the game take place there. Indeed, very little story is ever conveyed to the player in section 4. (Occasionally a document will be written there for story purposes.) The story mostly takes place in sections 2 and 3 with occasional moves in one. Reinforcing this focus away from the top sections is a colour scheme that favours more more colours and higher contrasts in sections 3 and 4. Players are encouraged to ignore the throngs of immigrants who queue outside, and are trained to ignore people the moment they step out of their booth. This is one of the key reasons why the suicide bombings are often as shocking as they are. Go back and play Day 6 again; the shutters of our booth actually close before the bombing occurs purely to give the player time to worry, wonder what's going on, and find the suicide bomber walking toward the guards at the top right of section 2. (Placed as far away as possible from our focus on the line between 3 and 4.) Spotting the bomber on day 2 is much simpler; he jumps the wall right near our focus and the shutters snap down as he does so.
Another way this ignorance is reinforced is by the differences in size between the left sections and the right ones, and how this affects immigrants upon being denied. Since section 2 is so long, an immigrant accepted to Arstotzka takes a full 29 seconds before moving off screen. By contrast, one denied takes a mere 15 seconds, nearly half as long and for most of the time vanishing against the queued masses. Out of sight, out of mind. The player is encouraged to think more on the people they've let in than the ones they've thrown to the wolves.
That's reinforced by one other clever touch placed in section 2.
While the barricades marked by the red square have no in story purpose, almost any player who has played Papers, Please knows what they are: They represent the point at which you will receive a citation if you've missed something. Thus, the player is drawn to look at the immigrant they've let in for at least that long. That distance is roughly twice the distance between the beginning of the queue and the booth.
While Papers, Please works on a lot of levels (indeed, the layout is a fairly minor one) it still shows the amount of thought that went into the title. The gameplay is designed at every stage to hyper-focus the player, leading them to ignore the humanity around them and instead perform their technocratic duty, while still leaving on screen the various nods to humanity, letting the player spot them in their own time and consider them later.