Mindustry is a free and open source sandbox factory tower defense game for Windows, macOS, Linux, and Android. It is released under GNU General Public License v3.0 and written in Java. In this game you need to create supply chains of conveyor belts to feed ammo into your turrets, produce materials for building, and defend your buildings from enemies. It supports multiplayer and large-scale PvP unit battles. This game comes with more than 24 maps and a build-in map editor to create maps.