Didnt feel too much of an intensice to keep on shooting since thats what makes hell break loose, also the player could use a bit more variety. Perhaps something like when you hit the dices they break and give you XP, and you can get other random upgrades to keep the theme intact.
but other than that, clicking extremely fast and making a horde appear is way more entertaining than i would like to admit I spawned so many at once they clipped through walls 10/10