Building the Great Wall of China - Level 21 ~ 23

Level 21 Upgrade camp, chop down woods, and upgrade camp again. Build sawmill and farmhouse first, then hunter's cabin and steelworks. Remove rocks in the wall site to get stone and remove obstacle. While building the wall, buildstone mine and warehouse. Upgrade steelworks and stone mine for more resources. Get 2 statues and build the wall asap. In this level, red dragons will constantly destroy buildings. That's quite annoying. Repair all broken buildings immediately. Level 22 (From 6:37) Upgrade camp twice while filling in the crack. Collect every food and wood in the lower area. Build sawmill, farmhouse, steelworks, then stone mine. Build the stair to the wall to build the wall and collect masks. Upgrade stone farm and build warehouse if you have extra wood. Level 23 (From 12:55) Upgrade camp and remove huge heap in the left. Cut down all available wood and harvest berries. Build sawmill and the stair to the lower area. Collect berries and wood in there. Build hunter's cabin and warehouse, then build steelworks and stone mine. Upgrade camp and start building the wall. Collect resources needed to build the fort as well. If you're out of stone, collect vases while waiting for stone production.