Unity - The multiplatform game creation tools for everyone.
The Stanley Parable - The Stanley Parable is an Action, First-person Perspective, Puzzle-Platform, Exploration and Single-player video game created and published by Galactic Cafe.
Godot Engine - Feature-packed 2D and 3D open source game engine.
Portal - Financial Aid Award Letter, - Messages and Calendar, - Grades.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
The Talos Principle - Philosophical first-person puzzle game.