Board Thread:Plants vs. Zombies 2: It's About Time/@comment-24725728-20140512192458/@comment-24657844-20140515191942

Mr. Boss-inator wrote: I think they will move DA between AE and PS because since we have world keys they can release worlds in their order. Worlds before AE will be in their order too. I think you don't need first level to appear on the left if difficulties of worlds are same. AE can be still first world to unlock but not first world in the list. Time Period isn't something that determines where a world is placed. As Pvzgamer said, the difficulty is more important. You can easily notice, that with each world, zombies get tougher and tougher.