Top 3 simulator-game open source projects

The PyOS project is an orbital mechanics simulator, entirely coded in Python, which uses the panda3D engine. The acronym PyOS stands for "Python orbit simulator". Feedback is appreciated !

Unrailed! simulator using C++ with some reinforcement learning and Unrailed! AI using Python with OpenCV

Lifely is a text-based life simulator with no graphics. Some features might be unstable as of now.