yes you can see the texels of the lightmap (size 0.1u) and yes there is a staircase effect, but to keep it simple, i will keep it like that (also i like this old school graphics style) however, if the lighting shading would be calculated considering a kind of normal map representing the reliefs on the floor, wall, ceiling, this would greatly improve the look, i admit it...(it is way easier to use lighting shading on vertices + stencil shadows!!!)
first time you most likely see this effect in your life : a per texel spotlight ! (the lighting/shading is on texels, it is like real time lightmapping, but for a spotlight)...too slow to be used in real time on my computer (around 60-70ms to calculate/color), but hey the programmer within you will appreciate the effort
Is there no optimisations you can do to make it real time?
just dont overcomplicate it..it started nice and simple