Werkkzeug
Farbrausch's demo tool, in which textures, meshes and scenes are built from stacked operators instead of stored as data.
Werkkzeug – German for "tool", with one k too many – was Farbrausch's answer to the 64k limit during the 2000s. Artists place operators like tiles on a canvas – noise, blur, colour correction, extrusion – and wire them into a tree. What ships in the final production is the recipe, not the result; everything is computed when the program starts.
That is how .kkrieger squeezed a complete first-person shooter into 96 KB. The tool was also released publicly and used by other groups, and its source was published in 2012. The approach – node graphs for procedural content – is now familiar from considerably more expensive commercial software.