I broke through to stage 7 on a single credit last night. It took all of my stocked lives to kill the stage 6 boss. Even then, it wasn't my highest score of the night. I netted 1,3xx,xxx in stage 6 a few runs before the stage 7 break. My camera battery was dead so I will take pictures of the score board tonight.
I finally figured out how to use Lisa most efficiently. Her mech form is much more powerful if you don't use her options, which is exactly the oposite of Keith and Lloyd. Because of this, she is more likely to get a higher special meter bonus at the end of the stage.