Here is Wikipedia's summary about sales of the previous games:
Consumers purchased 1.5 million copies of Ninja Gaiden and Black to August 2007,[135] with the bulk of these sales going to North America and Europe. According to the NPD Group, in its first month Ninja Gaiden sold 362,441 copies in the United States, with Sigma selling 63,637.[136][137] As of April 2008, 470,000 copies of Sigma have been sold in Europe and North America.[138] These sales figures reflect Tecmo's decision to target the non-Japanese market. Japanese gamers were not particularly excited by the games—according to Itagaki, only 60,000 copies of Ninja Gaiden were sold in Japan in the four months following its release,[28] and Famitsu gives a figure of 76,095 copies for Sigma in its first six months.[139] The critical and commercial successes of Ninja Gaiden have led CNET and GameSpot Asia to induct the game into their Halls of Fame.[140][141]
In light of this, it's not so bad, although I would expect a sequel to be more frontloaded.
My Mario Kart Wii friend code: 2707-1866-0957
