I really love this kind of articles, so much to learn.

If you render columns instead of rows you can render near-to-far without a Y-buffer and with zero overdraw. :)

It's interesting that the color maps seem to have shadows "built in", so that you get a 3D bevel effect from just looking at the color map.

When this was first posted I made a game with a port of this approach to AGS Engine. Nowadays AGS is much faster since we have improved a lot of things, but this wasn’t the case at the time, so I had to make a few little tricks to make the rendering work well with the engine at the time.

https://github.com/ericoporto/i_rented_a_boat