Launching just gives a 'Shader Compile Error' both through the itch launcher and with a direct download.
I figured it out after testing on a few computers. The problem with the shader was this line: "precision mediump float;" This is required for WebGL (and the browser version), and most PC shader compilers ignore it so I thought it was safe to leave it there. However, a few compilers crash when they see it, so I simply removed it from the non-webgl version.
Thanks for the bug report! Try downloading the game again and let me know if it works.