In Brandon Chung's Gravity Bone (of Blendogames), you play as a spy in two simple missions: poisoning someone's drink and delivering it to him, and taking photographs of mechanical birds. It's in first-person with block-style graphics, and even a little bit of first-person platforming. The gameplay is pretty straightforward (functional and intuitive), and it's over fairly quickly (almost prematurely, it seems), but it's enjoyable enough while it lasts. The ambiguity of its ending sequence lends itself to artistic interpretation, if you're so inclined. Even if you're not, it's an interesting concept nonetheless. Get it for free here.