Make the brownie mix according to the box instructions. Spread in a 13x9 cake pan.
Bake in 13x9 cake pan for 11-14 minutes (10 minutes less than the lowest recommended time on the box).
Take the pan out of the oven. Layer remaining ingredients in the following order: sprinkle mini marshmallows over the top of the brownies, then crumble graham crackers on top of marshmallows and finally sprinkle the broken chocolate bars all over the top.
Return to the oven and bake for another 10-12 minutes.
Let cool completely and then cut into squares for eating.