Left click:
regolith -> dirt
water -> dirt
plant -> grass (+1 point)

Right click:
dirt -> water
grass -> water

Automatic (random-based):
dirt+water->grass
grass+water->plant
plant->virus
R - restart

Collect as many points as you can before you can't anymore (or before you get bored).

Made using Godot, a completely free and open source game engine.

First time doing a 3-hour game jam, and here are some lessons I should have learned by now:
1. Make a plan first. It doesn't count towards the 3 hours, and even if it did, it saves you more time later.
2. Keep your code as simple as possible. The more complex it gets, the more likely you'll get an error and the harder it will be to fix it.
3. Keep the assets as simple as possible, especially if you are making them yourself. You don't have the time to make your game pretty, just enough to make it at all.
4. A bit niche, but use enums and constants stuff. It would save me a lot of refactoring pain.

EDIT: oh yeah, and
5. Test the smaller parts of your code before you test the larger parts.

This was a solo project by me.

The only external asset that made it into final game was the soundtrack.

"Rynos Theme" Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 4.0 License
http://creativecommons.org/licenses/by/4.0/ 

There's also https://grumpydiamond.itch.io/small-grass-tileset-16x16 but it's unused.