Just give it a minute
After a few seconds the game will un freeze and the humans will come from offscreen, once they reach the center they'll spread out and you can continue as normal. Seems to mainly happen on the same level every game for me, and sometime at a random other one. Doesn't really detract though, just a bit of waiting.
sometimes it gets stuck and humans doesnt appears. but it was a great game! :D
I can die happy
2mil+ points and all unlocked. It's a zombie new year.
cant wait for the next one intense game and simple 2 word that i like when i talk about a game.!