Sick!
My first thought is that since the outer enemies are shooting at you, it would be cool to shoot back at them. Maybe when you roll a number, you get that many shots to fire back at enemies.
My main question in playing it was "Do I play it slow or should I roll constantly." I got my score by mashing the die roll button and just trying to stay alive in the bullet hell that ensued :) My slower strategy involved trying to crush every enemy I could before moving on, but playing the slower / more strategic game didn't pan out too well since the outer enemies were putting on constant pressure.