its a slow time in japan. look at the ds its under 100k
also, NA wii sales went up 20 % last week so maybe they shipped heaps there for metroids release?
its not even doing badly. i mean if the numbers stay that way, wii will sell 200k in one month and if they stay that way for the ps3 it will sell 80k in one month.
i dont think nintendo has anything to worry about.