An open world zombie survival game for Android

Hello all!
The game is based on waves that get increasingly difficult with more zombies spawning each round.
As the waves increase so do the zombies damage per hit and their running speed.
I have added a new user login/registering system. You can now save your level, exp, position, gold etc!
To register just enter a username, password & email and you're done!

Please leave any feedback / criticism below, let me know anything that can be improved or added

Google App Store listing