@wertimer @kirby download the iso from here https://www.templeos.org install it on a virtual machine and read the code. Terry wrote examples for most of the stuff that exists in the system, and there's built-in documentation for pretty much anything you'll ever want to do, unless you get into really esoteric stuff.

Alternatively, download BlazeItFgt 2020 or DigGaym (the other two games are pre-compiled and run as binary blobs) and study the source code for those games if you want to jump straight into templeos gamedev. https://scumgames.neocities.org