"Art of War - Basic Combat" Too hard

I wanted to get the gold medal, but after several failures I went to see tutorials to help me.
Unfortunately, the tutorials were all released around October/November and currently, the enemies in the mission don’t behave at all the same as in the tutorial videos.

The gold medal is almost impossible to have…

Is it a bug?

I managed after a lot of practice to get 0 deaths in basic combat. But it’s very tricky.

I made a video explaining my strategy if you want to give it another try: https://www.youtube.com/watch?v=xm8FRDIUOVw