Code Zero is a free-to-play multiplayer first-person shooter with online competitions in a "5 vs 5" format, similar to the early versions of Counter-Strike 1.6. However, instead of the usual terrorists and special forces, the main characters are anime girls. Each player has three lives, and once they are spent, they are eliminated from the round. Available weapons include shotguns, assault rifles, pistols, grenades, and knives.