Players move or advance through the game by gaining experience from killing enemies and finishing quests that are given throughout the game. If a player has enough experience, he will gain a level. There are 120 levels a player can get. Each level is made higher by each expansion by 10 or 5. They may continue to grow even more powerful at the highest level by getting items from bosses in instances and raids. "World of Warcraft" has developed a community of 'raiding guilds' that compete with each other for 'first kills' on bosses in new raid instances, dungeons that require 10 to 25 players to work together to take down really hard Alia bosses.