It already is. I'm 2/3rds of the way through SR3 and I can point out individual instances where they've made fun of pretty much every genre and mechanic to date, ranging from zombies and overuse of gore to the ridiculous inhuman action sequences and quick time events characteristic of so many games. My personal favorite is where they stick you into a flat, two dimensional computer level and pit you against enemies that seemingly can't kill you if you try in any sense of the word (walking through the level without shooting counts as "trying"), all while your "avatar" varies between completely ridiculous models (a toilet with a gun is particularly memorable ) and a skinless, totally generic male body.