The core gameplay of Papers Please goes like this: a person hands you their papers, and you drag them to your desk and look for discrepancies. Every line can have something wrong with it (e.g., it may say the person is 160cm tall when you can see that their taller, or the passport number may not match up with the number on something else). So you have to look through it all before stamping approval.
If that doesn't sound like fun to you, you may be right, but for those still interested, you'll probably enjoy this game for at least a while. There's a certain stress to looking through the papers, not knowing if they're legit, knowing that if you mess it up, you'll get another citation and if you take too long, you won't process enough people and will end up short on cash, which you don't want to be.
With just the core gameplay alone, the game would be something new, but then there are colorful characters mixed in with the regular entrants. Some are just one-offs with a sob story or some kind of banter, others will be part of little story arcs that can make you some extra money. The biggest story arc is that of a revolutionary movement that asks for your cooperation in taking down the government.
Everything looks just right within the bounds of the EGA-style graphics. The random faces, the soft stressed breathing, etc. With its minimalist design and attention to detail, the game can really pull you in and make you feel like you're there, examining papers with bureaucratic efficiency and making ethical decisions on the way, some of which may change the goings-on in Arstotzka. There's a certain rhythm to it and even though it's just a game it can feel good when you're moving along quickly with no errors.
This is separated from a lot of the other "art" games out there by being backed with very solid gameplay, if you're into what it offers. Overall, for what it is, I give it 3.5 out of 4. The only complaint is I would have liked to see a few more characters in the story mode (even though it already has quite a few), and to see a little more randomness as to when the less important ones appear, just to give it a less "fixed" feel on subsequent playthroughs. There is some variation (for some minor characters, it's random what they look like and whether they have discrepancies), but I feel there could have been more randomness still.