i still say 'romp through childhood'
i mean, you can go ANYWHERE with it. you could start with the kid playing things like cowboys and indians, cops and robbers, knights and princesses, that kind of innocent thing. then he hits puberty and everything gets dark, gritty, etc, and all the characters you 'grew up' with are suddenly drug addled and complete badasses and generally murder people thoughtlessly on a regular basis. then, he hits the teenager years where everything REALLY begins to go south, the kid imagining things mostly comprised of eldritch abominations, really really stereotypically metal monsters, atomic warfare, death and destruction, leading to the final boss (which could be the kid's mentality, or his anger at his old childhood -you, the blockhead- not succumbing to his 'grown up' reasoning).
then, in the after-story or the post-final-boss, you have reconstructions of all the stages that the kid has gone through. the cowboys and indians, the cops and robbers, etcetera, have developed into legitimate characters because of the challenges of his hormone-crazed mind, and you can challenge the kid (or should i say, college student?) to a sort of bonus boss fight, much harder then the original encounter
