Being inspired by this excellent article by Surma on image dithering, I started by adapting TinyGL (a well-known OpenGL 1.1-like software 3d graphics renderer) to run on a pico and to render 1-bit dithered images.

I managed make it run and ported some demos such as glxgears and Sproingies from Xscreensaver. Although, it needs a lot of optimization to run smoothly.

The other thing that I've tried so far, is to adapt Graham Sanderson's RP2040 Doom port. This worked out pretty well, I managed to get an acceptable image quality so the game is somewhat playable.

Here is an E1M1 speedrun: