What our group of five came up with was a game which would abuse a loophole. We came up with something that had 5 minute play sessions, but which also had multiple divergent paths as well as multiple areas and three diverse characters. It was based on the 'save scumming' principle, which comes from games that allow multiple choices (mostly RPGs): Do something, then reload to see how it could have been done differently. So for our game you could play it, then be encouraged to start up again and see how you could have done things differently.
It was story focused, but did not have dialogue or anything written down: Everything would be driven by what the player did and saw to tell a small, personal story. The setting was post-apocalyptic, but tried to offer something different by setting it right after the bombs fell. The boy had to go into the city to find medicine for his father, the old man had to go into the subways to retrieve a photobook he left behind while he fled the city (the only keepsake he has left of his friends and family), and a teenage girl that has to go into the woods to hunt for food. It could be monetized with an initial sale that offered the three standard characters, and then it could be taken further by offering new modules, each with (a) new character(s) and/or area(s).
