Actually, programming homebrew for the NES and SNES, I was surprised by how similar my experience was to learning OpenGL. You can't plot individual pixels on hardware like that, you have to fill CHR memory (like textures) and create arrays of sprite data (like triangles) to upload to the hardware accelerated unit of the console.

While it's totally true that you had to be very "close to the metal" in everything you do, I feel it's not that dissimilar from coding C and OpenGL today, in terms of the overall flow of your project.