Comment by CannisterFlux

This explanation [2] on how the 3D was achieved may be interesting to you. The game X [3] used a similar technique to draw 3D on tiled backgrounds on the even more limited hardware of the old black and white (green and yellow?) Game Boy.

[2] https://www.bbcelite.com/deep_dives/drawing_vector_graphics_...

[3] https://en.wikipedia.org/wiki/X_(1992_video_game)