I love the idea behind the game - zombies killing humans. Zombies have their story to tell and I want to hear more.
It would have been nice to have instructions at the beginning of the level, that way the player knows what to do. I did not notice the "information button" at the bottom right of my screen until I had figured the game out. Also, having feedback when the enemies reach your wall would have been helpful.
I enjoyed tapping and the bullet effects. I see myself playing this game casually (earning points, unlocking rewards, unlocking new zombies, weapon upgrades, and so on).
I hope you continue working on it. I would love to play an updated version. Well done Kizito and Ysabel