This is a sweeping generalization, but I found this commment to be fairly descriptive and funny:
Social gaming is big in Europe, and FPS and Action games are big in the US. Japan likes gimmicky tamogotchi-like games with fuzzy creatures and characters with hairdos that defy gravity.
For the record, I’m currently playing one of those gimmcky games from Japan, and I’m liking it.
This sounds like something my wife showed me in game informer.