by ironhide1
I can't vouch for the age groups, as I have only played this with adults. I would think that it wouldn't be too difficult for that age range, especially if they're used to old school Risk.As for three players, we have played exclusively with three. Our games probably average in the 1.5 hour range, but we are also a fairly methodical group, jockying for continent bonuses and cards before we strike hard. They have however been as short as 20 minutes and as long as 2.5 hours.
Our games started off as more territory control and capture the board, but have evolved where wins are won other ways now. It just took us a few games to get out of the old school Risk mindset.