IMO, I never thought Bioshock would be an instant system seller. In the US, you really don't see any one game really move alot of hardware on a given week, save for a few uber-games (such as OOT on N64).
Bioshock will move a few hardware units, but it won't be over a specific one week. Hopefully, it garners enough interest and looks from perspective owners to jump in on a X360 in the near future.
Back from the dead, I'm afraid.







