At the end of the game, you will find yourself in a greenhouse, where you need to solve a puzzle with a chemical solution, and thus destroy a giant plant. To solve this, you need to properly mix the chemical between three different test tubes.
First of all, you must put the cartridge into the synthesizer: the goal is to fill the left side cartridge up to the red marker. Please note that each cartridge has a different height and may contain a certain amount of liquid.
First playthrough
Second playthrough
How to chill a herbicide
Now that you have synthesized the herbicide, you must cool it down: