Rampart Arithmetic

Defend the five-lane rampart through three visible waves. Towers occupy the bottom row and shoot only their own lane. Level-1 towers deal 1 damage within two rows; higher levels deal their level in damage with longer range. Recruit costs 2 coins and places a level-1 tower on an empty bottom cell. In Move/Fuse mode, select a tower and an adjacent bottom cell: move into empty space or combine two equal towers into one higher level. Every recruit, move, fusion or Wait advances one beat. The towers fire before enemies advance. Escaping enemies remove 2 wall health. Kills earn 2 coins. Two preparation beats separate waves. The final central armored enemy reduces every hit by 1, so level-1 fire cannot hurt it. Preview: wave 1 lanes 2/4, wave 2 lanes 1/5, wave 3 lanes 1/3/5 with armor in lane 3. Keyboard: Tab and Enter/Space operate buttons; R restarts.