Stage 24 is the one where the enemy CPU has a single high-powered Harvest warrior, and you start out with a handful of people. There's only a precious minute or so before the warrior reaches your first person. Any tips on how to beat this stage?
I finally beat it using this strategy:
Play as the Goddess of Water — the approach is to have fast growth, but a slightly stronger attack than Harvest.
As soon as the game starts, begin landscaping so that everyone can build houses. Don't worry about clearing enough open space to build castles — that takes time and too much space; instead, keep ejecting guys so that they build more small houses. Each small house grows, so the more, the merrier.
In the same vein, when the Harvest warrior reaches your first house, eject a guy just before they meet so that the warrior has to fight two guys. You will lose, but each fight causes the Harvest warrior to split in half, meaning that each new warrior has half the health; they gradually lose health as they walk around.
Use rain a lot to help your houses grow. For some reason, the Harvest warriors will not sweep straight across the map — they tend to go back and forth, which is where the key to survival is. If they skip a house, keep ejecting guys from there to multiply the houses in that area, and for the houses they do attack (they tend to mass around even though only one fights at a time), keep ejecting guys so that they fight additional guys (and thus split again after each fight).
Eventually, they go back and forth so much (and there will be like 20 warriors, each slowly losing health just by going back and forth) that eventually you start winning fights against them, and/or they just die because they run out of health.