By the end of the mod's development, the team was working directly with the Unreal Development Kit and had created a Java-based tool to help manage the changes that the mod was making. According to one of the mod's core developers, Amineri, the mod started as a series of changes to the base game's configuration file, and grew more expansive as the team's capabilities grew. The mod was developed by Long War Studios, a team that came to include four core members, with assistance from 29 contributors, 20 voice actors, and three members of Firaxis Games, the developer of Enemy Unknown and Enemy Within. Long War adds a significant number of new soldier classes, abilities, weapons, armors, and usable items, and also introduces new features, including soldier fatigue and improvements to alien units over the course of the game. Almost every aspect of the original game is altered, creating a longer, more complex campaign that presents players with more strategic choices and customization options. It was first released in early 2013, and it exited beta at the end of 2015. Long War is a fan-made partial conversion mod for the turn-based tactics video game XCOM: Enemy Unknown and its expansion, XCOM: Enemy Within.