Protect your city from invading enemies by strategically placing defences towers along the canyon rim. Your task is to build the ideal defense system to protect your city. Build your defense in preparation for the attacks. The next wave is displayed at the bottom Of your control panel. You build your defense using the different towers available the Control Panel (shown on the right). The tower will attack enemies that come within their shooting range. Different towers attack different types of enemy (ground and air) so plan wisely. To build a tower first make a selection in me control panel; then move the cursor to a vacant space on the map (on the rocks, not the road) and click to place. To proceed to the next attack click "PLAY' or press the spacebar.