(Game in question: https://ldjam.com/events/ludum-dare/52/harvester-3) I know there's only four hours left of the rating period, but I'd still like to get at least a few more ratings.

First, if it didn't come with your system, you'll need to install Python. This can be done by going to the official Python website, downloading the installer, and running it. Make sure to check the Add python to PATH option, as this is needed to use Python in the command line.

Next, you'll need to install pip. It usually comes with the Python installation, but if not, then you can install it by running the command python3 -m ensurepip --upgrade. If that doesn't work, try using py in place of python3.

Next, you'll need to install pygame. In a command line, simply run the command python3 -m pip install -U pygame --user. This'll tell pip to install pygame for you, into your profile (rather than globally.)

With pygame installed, you should be able to run the game by double clicking the .pyw file. If this doesn't work, first try renaming it to a .py file. This'll cause a command line window to appear when running it, but the console can safely be minimized.