I have been working on a tutorial series for LibGDX https://github.com/tyler6699/evoscape, I was planning on entering Ludum Dare 40 but was unable to due to family commitments so in around 4 hours I edited to tutorial to match the theme of the Jam.

This is a super quick and dirty edit, you have to interact with the green field to get food and interact with the lakes to get water. Once you have food and water you can run up to trees and feed/water to keep them alive.

When they run out of food and water they die, when more than 10 trees are dead its game over.