Interesting idea, but needing to click exactly on the towers made it tough to shoot. If you could click on the line between you and the towers, if would be easier to shoot (though that might be tough to implement, so I understand why you didn't do that).
At a certain point, the enemies build up so much anyway though, that there almost isn't any point to even try to kill them. You can circle them in a fairly easy patten and consistently dodge, so only new spawns are a concern.
Overall, a nice application of the theme, but like, without any incentive to fight, the game just, isn't all the fun after a bit cause I find myself just running around in a circle.
I could see this evolving into a roguelite (if you keep working on it), with different levels (featuring different enemies) that you move to after beating each level's boss, different starting equipment (like, a gun that could do a buckshot, but has knockback, or a beam between you and the pillars, but locks you in place for a bit) and some other items that you pick up along the way to increase move speed, or general attack damage, etc.