From the game's introduction:
Welcome to Heavy Ordnance, the second Roleplaying Game to use the Reflex System.
Heavy Ordnance is a satirical Roleplaying Game where the players play prepubescent school children with large military surplus weaponry. A nasty accident, involving some weapons grade plutonium and the cafeteria meat loaf, has blasted portions of your hometown into the many levels of hell; and all citizens the elder side of puberty have been turned into brain sucking monsters. Luckily, your Elementary School was built next door to the local National Guard base, and yourself, and the rest of your fifth grade class, have armed themselves. Now all you have to do is figure out which end of the bazooka is the business end, before the Principal smashes down the door and snacks on your entrails.