BOTDs should never imply so many grinding on a game (notably when game has mediocre controlling and balancing). Remember some of us have a life, a job and other things to do ...
As soon as you get walls you can do a trick : Block both entries with walls, then break one piece of wall at one of the entries, kill all zombies coming in a row (use boxes to refill ammo), then rebuild wall. Then go for the other entry, break piece of wall, kill the remaining zombies, then rebuild wall. Repeat.
Calm, peaceful and relaxing atmosphere. A pleasure to explore the forest looking around for treasures. Except that annoying snake. (anyway awesome game! I remember the 2nd game, a great one too!)
@Stargeddo Change the subject message to "Report a missing Card, Badge or Bounty" on the feedback page and then you can send your screenshot. (Alternatively you can use Game Bug link under the rating stars to get to the feedback page). I was able to send a report, let's see if Kong replies to it. I'm pretty sure they are aware of all these BOTD and challenge related problems right now.
Nice enjoyable quiz, all those hours spent on Google Maps came in handy. But please Kong FIX YOUR API !!! (BOTD does not work, other badges do but if I refresh the page they all disappear... And where is the report link? :/)