The shader is done and the software rendering has been improved a bit! For the shader I was a little inspired by how Marclurr had done. It's still a bit messy, there are a lot of points to improve and also things to add, I might do a separate topic if I really go further than that.
If you want to be inspired or even copied it's free
I didn't add the ceiling although that's easy to do now that the floor is done, but for the simple reason that I thought it was cool to be able to deifne several diferent floors with negative values in the map array, then I what do i do for the ceiling? So I preferred to do nothing for now, but some slight shader changes will suffice.
You have the straff with Q/E or A/E and you can also switch maps with M. The window is also resizable live. You just have to set the second parameter of the raycaster:init method in main.lua to false to try without hardware acceleration. You can remove and put the textures you want, it simply won't display them if they aren't there.
I'm quite jealous of your single draw call implementation, I originally thought of doing the mine the same however I decided against it as I didn't want so many branching statements in a shader, but it looks to have zero impact on performance and is much neater. Running side-by-side on my laptop both yours and mine have more or less the exact same render time of <1ms.