TL;DR A smooth and beautiful tactical game with very few issues. Definitely worth the purchase.
Story
In Edo period Japan, the Shogun brought peace to Japan by winning the war. However, some conspire against the shogun to plunge the country back into strife and usurp power. In order to thwart this plot, the Shogun's most trusted samurai retainer assembles four other companions to sabotage these rebels and uncover the mastermind hiding in the shadows (literally calling himself "The Shadow" in Japanese) and bring him to justice.
The game's plot is told through in-engine cutscenes between missions and character conversations in the midst of a level. The plot is pretty standard fare, with very predictable plot twists. While the main plot isn't really anything to write home about, the main characters are pretty endearing and fun to hear bantering with each other. The Japanese voiceover is also stellar.
Gameplay
Shadow Tactics is an isometric real time tactics game with 13 missions. You control a team of five characters from a top down perspective against a map full of baddies. Each character comes with a pre-defined set of items/abilities: a melee weapon (or sniper rifle), a unique ability, a distraction option, a handicraft pistol, and a bandage set. Although that doesn't sound like a lot of variety, each character has their nuances with the items available to them. For example, one character may distract enemies by throwing a rock and only getting them to turn away for a few seconds, while a different character might send a trained raccoon dog to make cute noises to get all the enemies preoccupied asking the important question - who's a good boy? Some characters are nimble and can climb vines are grapple to the top of a building with a hookshot, while others require conventional ladders. Some characters can pick up enemy bodies (a certain powerhouse can even carry two for the price of one and just throw them onto other enemies!), while the less brawny characters can only slowly drag them on the ground, and some can't move bodies at all. So you always have to consider which character is best for a specific job in a specific situation.
While you technically can go on a frontal assault, your characters don't have much in the way of ranged options, so you can easily get outnumbered and killed if you don't keep a low profile. Although classified as a stealth game, you'll find that it's more of a puzzle game: figuring out how to take out how to take out Soldier A without being seen by Soldier B or C, who either have direct line of sight on Soldier A, or are supposed to regularly meet up with them and will get suspicious if Soldier A is running late. Oftentimes, figuring out how to get through a segment will result in spamming F5 and F8 until you get it just right, but at least the quickloads are fast. Usually, there's more than one way to get the job done, and even more than one route to take to your goal. Your mileage per level can vary anywhere from 2-4 hours if you're meticulous and take your time, to 1-5 minute speedruns when you figure out the most optimal path. Nearly every level comes with some new gimmick to make things more interesting, and each level comes with 9 bonus challenges (badges) for some extra replay value.
Overview
The Good
+Smooth gameplay
+Great aesthetics
+Great Japanese voiceover option for immersion
+Fun characters with individual strengths and weaknesses
+Characters can be given instructions to carry out actions concurrently
+The environment of the level affects gameplay mechanics
+Game allows both pacifist and kill-all runs in most levels
+Multiple ways to go about each level
+Can replay missions in any order once unlocked
+Each level has badges for playing the level with certain handicaps for some extra challenge
+Nice soundtrack
+Runs decently even on a non-gaming laptop
+Demo available
+Save reminders
The Bad
-Poor pathfinding
-Alarms are near-instant
-Save-scumming simulator
-Linear story with on-the-nose plot twists
-Not much variety in gear