Still unmatched. Worlds that actually feel alien, gameplay that feels just good enough to be engaging, excellently told story with environmental design and zero dialogue, THAT soundtrack.
For the most part the exploration/progress ratio is done well, but there were a couple times where I felt like I was bashing my head against a wall for hours, finally caved in and checked a guide for where to go next, and being in disbelief at how I was supposed to figure that out.
Still, this is probably the only Metroid game to have it all. Highly regarded for a reason.