After a little while you know the most common opcodes without having to look them up, I still have some burned into my brain forever: LD HL,nnnn: 21 nn nn LDI

After a little while you know the most common opcodes without having to look them up, I still have some burned into my brain forever: LD HL,nnnn: 21 nn nn LDIR: ED B0 JMP nnnn: C3 nn nn CALL nnnn: CD nn nn RET: C9 ...etc..., and probably dozens more after getting back into the groove :)