This is Rixiot's game called "Nail". In Nail there are 2 teams, the Attackers and Defenders.
The goal of the Attackers is to breach through all of the castle's many defenses and destroy 2 sponge blocks hidden safely away at the far end of the map. The goal of the Defenders is to protect the sponge blocks with all their might for a whole 20 minutes.
The Defenders start the game 1 minute before the Attackers, which gives them a little window of opportunity to raid whatever chests they can from the Attackers, and get themselves settled safely within the castle walls.
(Team: Invaders)
last_username: http://www.youtube.com/user/MCLastUsername
three_two: http://www.youtube.com/threetwoLP
TiggyLi: http://www.youtube.com/user/TiggyLi
asdjke: http://www.youtube.com/user/AsdjkeAndBro
(Team: Defenders)
raid3r: http://www.youtube.com/ixraider
MonsieurApple: http://www.youtube.com/user/mrapplecomputer1
nocxx: http://www.youtube.com/user/nocxxHD
Etho: http://www.youtube.com/ethoslab
Map Download: http://www.minecraftforum.net/topic/1191368-nail-a-pvp-4v4-defense-map/
Click on a tag to search related videos