TOWER DEFENSE
Choose a tower, then click a grass square to build.
Speed accepts decimals: 0.5 = half speed, 2.5 = 2.5× speed.
Sets the next round and clears the current wave. Towers and coins stay.
When checked, click a tower on the map to fill empty grass squares with copies of its type and all its upgrades for free. Choosing Build tower fills with unupgraded towers. Existing towers stay.