Atlus announced today that it will publish the co-op remix of Metal Slug XX for PSP in UMD format only.
Sorry, digital folks.
There will also be six playable characters from the series, with a seventh, Leona, available via PSN for $0.99.
The game is slated to arrive at retail on February 23 for $19.99 and contains seven levels, and 70 missions.
More through Gamespot.