How do I get the APK on my android device? I played the web version. which is well laid out. In terms of gameplay (playing on browser) it did seem like i could just jump on heads forever and the challenge doesn't increase.
Suggestion: yes you can jump on heads but have the jump have a cooldown to avoid exploiting that feature. Alternately you could also perhaps introduce jumping zombies or something like that to mix up the safety of bouncing on heads forever.
Also I couldn't figure out how to reload. clickinging (web version mind you) didn't seem to do anything when it clicked "reload".
Suggestion: For the web version perhaps you could have all of the game controls correspond to key strokes like Z shoots X reloads or something like that. Also a toggle button for touch controls. This way people (most people) on web are going to not want touch controls taking up screens space
Really nice art and I love the way you have the remove ads / menus structured.