On level 10, when you fight the second stick fighter (two sticks), lead him back into the white house with the 4 health packs and 2 machine guns. When you get down the steps in the middle, he should get hung up and not be able to run any further. You'll hear the sound of his footsteps get very rapid and loud. Now that he's stuck, you can whale on him with your flaming 2 x 4 until he's dead without any loss of energy.