I really like the concept, especially how (I believe?) the bullets could hurt enemies on their way back to you as well as when you shot them. The game would really benefit from some sort of indicator of how many hits enemies take to kill, or maybe even some of the enemies could take less hits; sometimes I just felt like I was shooting at the same enemy for an eternity before they finally disappeared. Anyway, I really think the concept could be expanded on if you're interested in doing so. Maybe even design things in ways that really let the player put that cool reload mechanic to use! It's a neat game!