JPL78 on 22 July 2010
@disolitude, exactly and I'm sure we could think of tons more.
Personally I've already played over 3 hours and still have a little bit to go. If you count time from dying and restarting, or time spent trying to figure out the tougher puzzles, I think it could easily go 4-5 hours. Since there isn't an ingame clock its hard to tell, and the game has a really wierd way of making you feel like not much time has passed at all till you look at the clock and realize you've been playing for 2 hours straight.
