This game is awesome and will definitely win you over if you have any sort of fondness for puzzle/tactics games in general. If you enjoyed the original Desperados or any other similar squad tactics game, this is a must-play. You're constantly ambushing, picking away at vulnerable guards, and getting more and more complex/creative as more vision pathways open up. Later levels demand true understanding of the game's mechanics and timing. Levels are potentially ENORMOUS, and can genuinely take several hours to play through for the first time. The game is a little lacking in guard variety, but it makes up for it with some really great level/scenario design that stays consistently great the whole way. There are tons of challenges, alternate pathways and other options that give this game virtually limitless replay value. There's even a "level editor" by way of a save game modifier that allows you to add/subtract/modify all sorts of objects and guards from the various maps.
I really don't have much to say about it that's bad. The only thing I will say is that the regular walking state is completely pointless, making me wonder why the characters even have a normal standing state. Kate wears disguises, and I thought it would have you arouse guard suspicion by running in their vision cones or crouching while disguised. This would make sense because as it works, you can literally crouch-sneak through a Heavy's vision cone (who normally detect Kate despite her disguise) in front of lesser guards who are fooled by the disguise. There are also neutral areas now, so it also would have made sense to not allow characters to crouch in these areas, lest they arouse suspicion. No such handicaps exist, however, and thus there's really no functional point to ever having characters stand up. This would make sense if running were tied to changing states first, but you simply run by double-clicking, and by default, characters go right back to a crouched position once they reach their destination.
But don't let my pedantic argument bother you, I have 70 hours in this game and probably a similar amount of time in their previous game Shadow Tactics: Blades of the Shogun, so the minutiae sticks out to me more. Just go play the first couple levels and have fun. It's very much worth it.