When I say I just finished it, I should add that I started playing it 15 minutes ago. It's a short, short game that, except for one platforming sequence, should be beatable by everyone. I encourage you to give it a playthrough.
If I had to give it a genre, Gravity Bone would be a First Person (non)Shooter. It's all first person, but there are no weapons. Even the hammer you're given in your second mission can't be used on people. At no point in Gravity Bone will you be given any details as to your character, the plot, or why you have to snap pictures of five birds, who explode into fire afterwards. But along with the Iceberg Theory of storytelling, the game provides a unique, unified aesthetic. All of the graphics are blocky and pixelated, but with a strange sort of charm; big band music plays throughout. The game loves elevators for some reason. At the end of the second (and final) mission, your character has a couple of idiosyncratic flashbacks as he/she, well, you'll see.
I recommend the game because of its aesthetic, and also because of a chase sequence that occurs when someone (again, we're given little to go on, so it could be a spy, or a guard, or, perhaps, your character's babysitter from when he/she was 12 and really felt like he/she was far too old to have a babysitter, but would the parents listen, noooooooooooo, and so he/drove the baby sitter crazy all night and this is some sort of far-flung revenge plot on the babysitter's part. Far-fetched, perhaps, but not unfeasible) steals(!) the photos of exploding fire-birds you're painstakingly taken. Having no weapons, your only recourse is to chase her down, through air ducts and train tunnels, over steel piping and, memorably, up and down a Michael Keaton Bruce Wayne-esque dinner table.
The game is short, but memorable, coming across as a discarded good idea that just couldn't be made to fit properly into a full-form game.
