Purpose Increase a score counter at address score_counter and return. Don't worry about a carry overflow.
Code
	ld a,(score_counter)	;get current score
	inc a			;increase it
	ld (score_counter),a	;put it back
	ret			;return
	
Error You can use hl just like any other register. By just loading the address of the score counter into hl, you can modify it from there without having to put it back into memory. You save three bytes.
Fixed Code
	ld hl,score_counter	;address of counter
	inc (hl)		;increase it
	ret			;return