Note that the launch gauge in this guide may be different depending on the type of mobile device.

The objective is to slay the Orc Chief located on the bottom of the screen.
The right path is not ideal as a thorn shield soldier is blocking the way.
Use a cannon in the middle of the path to attack the Orc Chief.
Thorn shield soldier and archers will block the way if you attempt a direct charge.
Therefore, eliminate obstacles first and enter the middle path.
Clear the path with normal soldiers and attack the Orc Chief with charging soldiers.
Set the angle between 9.8 and 10 degrees when the stage begins.
The first objective is to eliminate obstacles on the left-hand side.
You can kill the thorn shield soldiers blocking the path by attacking a bomb.
Once you've eliminated the obstacles on the left, adjust the angle lower and target the right side.
Once you've eliminated all obstacles, adjust the angle to between 2.8 and 3 degrees.
Slay enemies blocking the middle path with normal soldiers.
Once the path is cleared, use charging soldiers to attack the Orc Chief.

Summary

1. Eliminate obstacles blocking the middle path
Send soldiers to the left and right and attack thorn shield soldiers and archers

2. Use a cannon in the middle of the path to attack the Orc Chief
Clear the path with normal soldiers and vanquish him with charging soldiers

* Please note that the angle may differ slightly and some may require a bit of luck, so it is best to find your best route referred to in the strategies.