3* on first 3 stages with baseline positions. You can swap a few arround, they are really clear.

Stage 4 is hard. You need to use the cannons. I placed 2 squads at the bottom camp, 1 to take the lower route and kill the pest, 1 to take the upper route and fire the cannons. The other 3 were located at the square surrounded by cannons with 3 charges. This way all shots were fired.

The bottom boss and the final boss are both really sturdy. So thats why you want to take at least a portion of their HP with cannons.

Was an easy 3 stars that way, making me have to do all stages once, except for the final stage, that was 2 tries. Good luck everyone!