From the Gamefaq's forums, and confirmed on NeoGaf: Confirmation hidden on Twisted Metal: Head On Extra Twisted. It looks this is EAT SLEEP PLAY's next title:
"ok, so the super gumshoes at Gamefaqs have cracked the code from the Dark Past video on the disc.
The code is displayed with random numbers throughout the video. If you put the numbers together, and match them to their alphabetic cousins, you get -
Twisted Metal is on PSTHREE"