I don't know how Nine Hours, Nine Persons, Nine Doors slipped under so many peoples' radars. Maybe it was bad timing. Or that funky name.
So what the hell is 999? It's sort of a cross between a visual novel and a point-n-click adventure game. You play a college kid, Junpei, who finds himself trapped on a boat with eight other people. The nine of you are greeted by a mysterious masked person named Zero and told you have to play something called the Nonary Game in order to escape. If you don't play—or if you don't escape within nine hours—you die.
Much of the game involves reading dialogue and (some rather over-the-top) prose, but you'll also have to solve puzzles in order to escape from a series of deadly rooms. These puzzles mostly involve gathering and combining items, old-school-adventure-style. There are also some random assorted brainteasers and other tricky obstacles to overcome.
Also, you'll have to play the game at least twice to see the real ending. Don't worry: you can fast forward through scenes you've already experienced. You have to repeat some of the puzzles, though, which is kind of a bummer. At least it all leads to some glorious payoff.
If that all seems interesting, go check it out! I'll have more coverage on its sequel, Virtue's Last Reward, in the coming weeks.