Not that Im saying Uncharted is bad game but some explanations would be the PC version (simultaneous I might add), BioShock was never bundled, and Halo 3 was released less than a month away from BioShock's release. If an 8m seller in the same genre of Uncharted is released less than a month away, its obviously going to affect sales.
Hmm.. early predictions for Uncharted 2 v BioShock 2 (360)?