Hey there, thanks for checking out the demo. This was done with Godot 3.x, so does not have SDFGI. Pretty much everything is baked. There are no real time lights. I used the ultra light map settings, and tweaked everything, it took about 30 minutes to bake. Reflections use SSR (mostly seen on the floor) but for the walls they are cubemap reflections. It used box-projection so it looks more realistic and correct, and also works well since the scene is boxy. The reflections on the graffiti was automatic when using a PBR material with a low roughness, combine with the cubemap reflection probes. It did take some time to set the boundaries and blending for the probes to get it to line up. This works well for like small reflections or puddles on the ground and that sort of stuff. The cafe window also uses it, but you can see the limitation on the resolution with a window that size, it doesn't look that great. No decals were used (Godot 3.x doesn't support them). All the the wall stuff is just high resolution 4K textures taken from real photos. On the phone booth the tags are using alpha scissor transparency, so sort of fake manually placed decals since Godot 3.x doesn't have them. Otherwise the reason it runs so well is that there is no real time lighting. Baking everything makes it much faster.