You can join a server and play, like Terraria except you don't keep your inventory across worlds. I mean my building skills suck, the stuff I build looks like hot garbage. Building in Minecraft is a difficult skill to acquire because the only way to really figure it out is through trial and error. Sure you can look at other peoples builds but the actual building process is way different, again much like Terraria where building and making it look good is very difficult.
Yeah it is hard to see what is going on. The mob farm was a towering structure that used water streams to move enemies around once they spawned. Mobs in Minecraft spawn in dark areas and since the structure was sealed, it was completely dark and the mobs would spawn on some platforms and walk off into the water. They were then pushed by the current to the center drop zone where they fell out of the structure to their death far below. There were some hoppers there to collect the drops from the dead mobs.
There were 3 layers in this farm, with a two block space between them so the normal 2 high mobs would spawn but the taller Enderman would not. There are a lot of game mechanics at work there but it is simple in theory. The mobs just spawned naturally in the dark and fell to their death pretty much. I only needed Creepers to spawn and die so I could get the gunpowder to make some TNT. Everything else I got from it was basically junk, like bones zombie flesh and arrows because I already have some XP farms with skeletons and zombies so their drops are worthless to me.
It took me a minute to figure out what you meant about made of feathers, nah that is just the explosion effect. It is made from gunpowder and sand. It is more realistic than most explosions you seen in games (funny that this is Minecraft). You are seeing the shockwave effect instead of a huge fireball like most games tend to do.