Piercing multiple enemies was pretty satisfying as well as watching the arrow bounce around. I died at the edge of the screen to an offscreen zombie which can feel unfair (although I shouldn't have been walking there). Maybe to counteract that you could have the zombies spawn on screen with a delaying digging out of the ground animation before they can hurt the player and move around.
I also thought that if you increased the speed of the zombies and player, let the player catch the arrow after a bounce, and had the arrow charge faster you could have a neat fast paced version of this game. You'd probably have to reskin everything though since zombies shouldn't be walking so fast.
I liked the enemy variety as well and overall the gameplay was still fun!