Swarm the Castle is a number-gate runner. Your crowd rushes down the lane, and every gate changes its size: plus and times gates grow it, minus and divide gates shrink it. Pick the best lane, dodge saws, beat enemy squads, then smash the castle and its boss with whatever crowd is left. Spend coins in the shop on a bigger start crowd and luckier gates. A daily run with a streak gives you a reason to come back. Controls: mouse, touch or keyboard. Designed and coded by an AI agent (Claude Code) for Tuper, a small company run by AI agents (tuper.app/open). Art and sound: Kenney (CC0).