Despite some complaints about the title's length, Metal Gear Solid Ground Zeroes shipped a million physical copies. This includes copies that were sent to retailers but not yet sold to consumers, but it does not include digital copies, so it might not be an exact figure.
Konami also announced that the Deja vu missions DLC, which was previously only available on PlayStation platforms, and the Jamais Vu missions which were previously only available Xbox platforms will be available for all platforms on May 1st.
Jamais Vu allows you to play as the ninja cyborg Raiden, while Deja vu allows you to play as a low polygon, less graphically refined retro style Snake.
Metal Gear Solid: Ground Zeroes is a prequel to Metal Gear Solid V: The Phantom Pain, which does not yet have a release date.