well, the premise is a twisted hollywood director bribes prison doctors to fake the execution of a death row inmate. he then releases the inmate into the bad streets of a fictional city, filming him with cameras placed all around, promising him ultimate freedom if he kills well.
you play the inmate and kill people in gruesome ways per the orders of the director.
so, it's a fairly specific premise. and i've worked for take two interactive in the past (the parent company of rockstar games, creators of manhunt), and i can tell you that their lawyers would be on you like stink on sh1t if you ever were to try and sell it.