The Extra Twisted Edition of "Twisted Metal: Head-On" includes the remnants of the cancelled game "Twisted Metal: Harbor City", a direct sequel to "Twisted Metal: Black". Harbor City was set to be an open world game similar to the "Grand Theft Auto" series. In Harbor City, players could exit their vehicles in order to walk around the open area freely. After a plane crash took the lives of six of the game's key developers, Harbor City was cancelled. On March 13th, 2007, the two-year anniversary of the plane crash, Sony Entertainment was anonymously given a note which encourages the Twisted Metal team to release the unfinished work to the public, showing disapproval over the idea to keep the project under wraps. The note was inexplicably signed by the six deceased crew members. Even though the team wrote it off as "a joke in poor taste", this convinced developers at Sony to honor the fallen by releasing the completed levels as "Twisted Metal: Lost". The walking stages are available as the "Sweet Tour" section of the game, in the "Bonus Material" section.
The real sequel of Twisted Metal 2
This game was re release in 2008 for the console PS2, that version is the same as the PSP but it have some changes for example: They change the theme music, Cousin Eddy don't speak in one part which in PSP, they change some Gas Can damage change, The health item is different, Transylvania is a new stage in the PS2 game and more things.
Twisted Metal 2012 was unofficially revealed by David Jaffe and the newly formed Eat Sleep Play in the previous Twisted Metal game, Twisted Metal: Head-On. Head-On presented a documentary where the numbers occasionally appeared on the screen. Once decoded, the numbers would reveal a message that said: "Twisted Metal will arrive on PS3."
Twisted Metal Head On is not mention in Twisted Metal 2012 game