This is the second world of the game, The only difference is there's no sun falling from the sky and you can't plant on graves and some zombies will be tougher after you complete a level in this game. There is a Level 5 mini-game called "Whack a Zombie" you defeat zombies by clicking/tapping on them. Start level 11-20, after you complete another world, see the instructions to go on to the next world. Complete 10 levels and then you will go to the next world.
Some levels are going to get trickier after you complete an level in this game. Remember, if you defeat all zombies in final wave on each level you can get the trophy to complete a level and move to the next level.
