XP is short for Experience Points. XP is gained after defeating an enemy or boss, whether it be by killing them, knocking them out, or otherwise incapacitating them. The amount of XP gained varies depending on the level or type of enemy it was. Destroying objects or completing certain interactions also gains XP. Completing quests, successfully passing encounters, or crafting items will also yield varying amounts of XP. When the player gains enough XP, they will level up one tier. Any XP left over will carry on to the next tier. The amount of XP needed to level up increases each time.