its a possibility that all characters are unlockable in puzzle kombat...
but no one has found any way to do so as of yet.
BUT! with an ar max, you can play as other character's and non-programed characters in it, just use the 'replace scorpion as...' code, and it will change scorpion into the character you want...
i dont know why but playing as a chibi nitara made me shuckle... i guess it was cute... and strange in the same sense...