MrT seems programming a Sinclair in ASM was really hard, seems the ClashColor, the effect when colors mixed, avoid this "problem" was really hard.
Thanks for the post, I thinked sometimes to do soemthink like Spectrum or Amstrad, but I don't have any idea to make this kind of graphics, I only come to my Head use Blender and Voxelize each Polygon of a mesh.
IF anyone want program a real Spectrum today or in Emulator, I read very good thigs about Boriel Compiler, it's a Basic written in Python and seems you can do nice things.