Ever since I first completed Zero Mission, I've thought of the game as "that sort-of-sequel to Fusion that wasn't quite as good". But now that I've just completed the game for a second time, I've come to the conclusion that I've actually been giving Zero Mission too much credit; there are few respects in which the game outshines its predecessor, and that's especially bizarre considering that Zero Mission and Fusion were developed by the same team.
 
The Good: Zero Mission's pacing is great... up until the point at which the original Metroid ended. (After that, the game awkwardly continues with a lengthy epilogue that doesn't really jive with the rest of the game.) Whereas Fusion had terrific graphics and fantastic level design, Zero Mission has merely decent graphics and respectable level design. Zero Mission may, however, have the better music of the two. (The game's best tunes should be instantly familiar to any Melee fan.) 
 
The Bad: Zero Mission's story is non-existent beyond a handful of still images that I hesitate to call "cut scenes". And the game's bosses are virtually all letdowns, since most of them can be quickly defeated by simply firing a stream of missiles at them until they explode. (Later bosses are actually easier than earlier bosses, since the strategy for bringing them down remains the same, all while Samus's newly-acquired Super Missiles make her 5x more powerful!)
 
The Stand-out Moment: The startling appearance (and re-appearance) of the game's first boss.
 
The Verdict: 7.5 (out of 10)
 
I can't help but note here that it took me less than three hours to beat this game. While I value quality over quantity, Zero Mission doesn't do itself any favors by ending almost as soon as it's begun.