Duke Nukem: Critical Mass was only ever released on DS, which makes the discovery of a complete PSP version all the more surprising.
David Gibson, a moving image technician in the US Library of Congress, recently stumbled upon the find when performing an inventory of recently acquired games.
I happened upon a DVD-R labelled Duke Nukem: Critical Mass (PSP),” he said. My first assumption was that the disc, like so many others we have received, was a DVD-R of gameplay. However, a line of text on the Copyright database record for the item intrigued me. It reads: Authorship: Entire video game; computer code; artwork; and music.
I placed the disc into my computer's DVD drive to discover that the DVD-R did not contain video, but instead a file directory, including every asset used to make up the game in a wide variety of proprietary formats. Upon further research, I discovered that the Playstation Portable version of Duke Nukem: Critical Mass was never actually released commercially and was in fact a very different beast than the Nintendo DS version of the game which did see release.
I realized then that in my computer was the source disc used to author the UMD for an unreleased PlayStation Portable game. I could feel the lump in my throat. I felt as though I had solved the wizard's riddle and unlocked the secret door.”
Gibson was subsequently, via the use of some PSP emulation software, able to access and structure some of the files contained on the disc, even getting as far as viewing a complete 3D model of Duke Nukem flying through the air.