Portal: 4 hours
Portal 2: 8 hours
Dear Esther: 2 hours
Most of Telltale's point-and-click adventures can be finished in about 2 hours
Braid is short enough that it has an achievement for a speedrun of under 45 minutes.
Beat Hazard can't really be finished, but given it generates levels from music, you can set your play session length simply by which audio files you pick. Same goes for The Polynomial and Audiosurf.
Portal 2: 8 hours
Dear Esther: 2 hours
Most of Telltale's point-and-click adventures can be finished in about 2 hours
Braid is short enough that it has an achievement for a speedrun of under 45 minutes.
Beat Hazard can't really be finished, but given it generates levels from music, you can set your play session length simply by which audio files you pick. Same goes for The Polynomial and Audiosurf.