Yep, I still know all the hex opcodes of the z80 (MSX) now so many years later. It was nice; just type them in basic, poke and go. I never, at that age, knew the assembler equivalents and didn’t know it was a think until many years later. I learnt c and pascal before having an actually z80 assembler. After that I moved on to Amiga where I did learn 68000 instructions to make demos and games.