I'm going to need some help with this please.
-What do walls do?
-What are Crazonium walls? What do they do?
-How do I download custom maps?
Walls ( green ) stop creepers for some time before the erode away .
Crazonium walls ( pink/red ) is walls that will stay there all the time .
But it's more to them that you will find out after you have played abit .
There is an link to custom maps on the top right corner , you should get enought info there :
Try some CUSTOM MAPS! (http://knucklecracker.com/creeperworld/viewmaps.php)
Another important thing to know about crazonium is that it doesn't let connections pass.
But ehm, walls? I guess you've seen enough of them in the story maps....