I personally think the C64 version of Krakout is the best Breakout-clone of the whole 8-bit era (and maybe beyond). Many extras, many enemies, various cleverly build levels and great playability. Played this for hours and hours as a kid and accumulated many extra lives... until in some of the later levels that little infamous terrifying ball-eating orb appears and you realize why you need all these extra lives. Still haunts me today just thinking of it. Great game.