The achievements in the game only add up to 970 points, whereas most games have a total of 1000. Apparently extra content was planned as DLC, including additional achievements, but it was never released.

When going to meet Rosa at the City Library, in the first room on the left after the objective begins, you can find a desk hidden behind a shelf. On the desk is a TV displaying an image of a detective badge, and connected to it is an Xbox 360 with a custom skin based on Condemned: Criminal Origins. Turning off the TV will unlock the Xbox Achievement "Silver Detective Badge". It's unknown if this skin mock-up was actually intended to be produced and released as a real product.