Without denigrating the work, I don't see anything special to it technologically speaking. To me it just looks like a perfectly normal 3D engine, just without the usual style of lighting and choice of textures. Use simple (read flat colour) texture maps with thick black borders, wrapped around your ususal poly models. Go for minimal vertex shading, maybe just a few highlights.
If anything, I'd guess the lighting model may be simpler than a standard vertex-normal based OpenGL approach so it might be even faster than 'realistic' looking stuff.
Still, it looks cool :-)
