Humanity

After collecting the Goldy under the hill, use the firearm command and then use the float command and the fans on the level to jump your people over the hill and shoot the others. Eventually you will make it to the 3 doors and will destroy them as you whittle down the others numbers.

Here is a full video walkthrough with all solutions, all Goldys, and achievements! (Timestamps in YouTube Description)

Before completing the level make sure you have destroyed the "Others" black gates

If you go to 2:16:08 on video below you'll see how I tackled this Trial.

2:16:08 – FIFTH WONDER ACHIEVEMENT