Rendering for a Console Without a Z-Buffer
The original PlayStation is not just a slow modern GPU. It is a different rendering model. That difference is the reason Polygon Engine treats PS1 rendering as a content and tooling problem, not only as a runtime problem.
The editor can show a clean 3D scene. The PS1 runtime has to turn that scene into ordered GPU primitives with no z-buffer, fixed-point transforms, small memory pools, and a very unforgiving camera near plane.