Can't say too much about the medieval stuff, but as far as the modern martial art sports go, I've practiced stuff from both east and west (kendo and fencing mostly, along with little boxing and capoeira). Anyway, the basics in all are the same, i.e. hit the other guy but don't get hit yourself. The major difference in my experience has been the way things are expressed.
At least the kendo practice had an emphasis on the group, most of the things were done as a part of a group and everyone knew their part/standing in the practice, whereas fencers appear really invidiualistic in comparison. There are teacher and students, but the tradition appears less rigid.
Apart from culture I really don't see much difference. The ideas are expressed in a more "spiritual" way in east, whereas the west favours mechanical expression. An example here is "kiai" versus "priority". In kendo, in order to score a hit, you must have proper posture, spirit and determination. In fencing, the priority one gets or loses is determined mechanically, but basically the end result is the same - attacker is the one doing the hurting, not the other guy.
In game terms, depends totally on your system.
