Keys: 1, 2 or 3 selects a squad. Arrow keys move the placement cursor. Enter places it. Space starts wave one; later waves start automatically. P or Escape pauses. M toggles sound. The 1×/2× button changes combat, wave timers and passive income speed together. Defenders and enemies block placement while occupying cells. Defenders stay still until an enemy enters their three-cell detection radius. Tap a defender, then empty ground to move or an enemy within detection to focus. Hold stops pursuit while allowing attacks. R cycles defenders, H toggles hold, arrows and Enter issue an order; Escape returns to squads. Moving units remain vulnerable. Defenders begin as level-one rookies and train automatically on waves two, three and four. Kills earn coins. Passive income starts at one coin per second during waves. The coin-counter button buys income upgrades; pausing stops income. Each cleared wave starts the next immediately. The arena gains one row and one column and zooms out, up to 15 by 15 for the final wave. Losing all tower health ends the run.