As short as the game demo is, I can absolutely see the potential here for this to be fleshed out further! I can definitely imagine this being a fast gameplay experience, either with long levels of wild timing of various shots (maybe even using different guns, with different fire rates and limited ammo counts), or lots of short-burst levels for the player to rapid-fire play through. You definitely have a neat concept here, so keep going with it if you feel up to it! Nice job so far! :D