Gunpoint takes sneaking around to an interesting new extreme by redefining what normally distinguishes one stealthy action game from another (this being the tools you use to make not being seen easier) and gives you the wiring of the entire building to play with. Fundamentally, Gunpoint is fun for the same reason the first two Thief games were fun; the levels are extremely non-linear, and your goal typically consists of "get the room being pointed out, then get out as un-harassed as possible."
The store page hype claims that you can rewire electrical sockets and enemy pistols, but these functions are only unlocked by limited use gadgets which become available after several missions are played. The majority of the gameplay experience consists of figuring out what daisy-chain of lightswitches, doors, and elevator call buttons will clear a path through the building and keep you out of the security guards' sight. This can become tedious and a little formulaic after a while, though it isn't enough to make me stop playing.
The story is fairly good if you enjoy sarcastic comedy, but wouldn't be quite enough to give the game a shining recommendation on its own. Gunpoint's gameplay is more than enough fun to overcome any of these fairly minor shortcomings, though, and this is a double recommendation for anyone who played a great deal of Splinter Cell, Tenchu, and/or Thief in the early parts of these respective series.