Based off of MattKC's video about fitting a game inside of a QR code and javidx9's video about writing tetris in the command prompt, I wrote a flappy bird clone purely in C. The (flappy bird) executable weighs in at 1081 bytes.
I also wrote a little 3D engine .
Install the C++ desktop build tools from the Build Tools for Visual Studio Installer, download/extract the latest Crinkler release (this project used v2.3), run the Developer Command Prompt, and compile using the included batch file.