weekly challenges that ask you to do more than just try and survive. scavenger hunt type stuff so you can accomplish something and progress even if you're not great at the fighting/building part. they also have 8-10 week long seasons that revolve around a particular theme which shakes things up and constantly changing the map and adding/removing weapons and supplies to change it up. At the start of this season, a meteor hit the map and leveled buildings and added random craters all over the place. since then there have been more minor changes basically each week. a lot of games inside the game and constant change.