http://www.animaprimerpg.com/main/node/11
Playing with two (one GM and one PC player) means missing out on character scenes among PCs, giving each other dice for maneuvers, and all sorts of other things, but it can still be fun. Playing with six or more people will slow the game down considerably, but you can give it a try and see how it works out for you.

With new rule in Group Competence, one player will never have more than one die.