I fail to see how a new IP selling 156,000 in only 2 weeks in the States can be considered a flop..? Looks like good sales figures to me, particularly when you consider the second week's worth of sales are still 2 thirds of the opening week. House of The Dead Overkill has made Sega a profit after selling over 300,000 units, so I'd say that getting halfway to making a profit on a new IP after only 2 weeks in a single territory is a resounding success.
It has had some very harsh reviews indeed (if the aliens vs humans war and storyline is so 'generic' and deserves dropping review points/marks then why didn't the same thing happen to Halo 3 and Killzone 2..?) but thankfully it hasn't affected sales too much. In fact, word is spreading on various forums that a great deal of those reviews can't be trusted and are overly harsh...and word of mouth combined with the viral marketing campaign by HVS appears to be getting results.