AssaultCube is a free, open-source multiplayer first-person shooter built on the Cube engine. Set in realistic environments, it combines fast, arcade-style gameplay with efficient performance and a compact download. The game is available for Windows, Mac, and Linux; its package is approximately 50 MB, and suitable settings allow it to run on older computers, including systems with a Pentium III processor or better. Its low bandwidth requirements make online play possible even over a 56 Kbps connection.

Players can choose from numerous multiplayer modes, including Deathmatch, Survivor, Capture the Flag, Hunt the Flag, Keep the Flag, Pistol Frenzy, Last Swiss Standing, and One-Shot One-Kill, with team variations available. The game also includes single-player bots, a demo-recording system, and several dozen maps. An in-game editor lets players create maps and collaborate on edits in real time, while additional maps are typically small downloads.

AssaultCube provides downloads, documentation, a wiki, forums, and community channels such as IRC and Discord for player support and discussion.