The first Metroid is now the best.
Metroid: Zero Mission is not really a remake. So much has been improved, changed, and thrown out of the original Metroid game that this new title bears little resemblance to its blueprint. Samus is still running around Zebes and shooting Skeeters, and she destroys Kraid, Ridley, and eventually Mother Brain. Guess what? All that happened in Super Metroid too. Was that game, considered by some gamers to be the best video game ever made, also a remake? No, because it played drastically differently thanks to the many new upgrades and moves at our heroine's disposal. Zero Mission takes exactly the same philosophy and amplifies it considerably, with even more moves and upgrades, plus an expanded story and some gameplay ideas that are completely new to the series. The end result of mixing all this stuff together just happens to be a masterpiece.
Please don't mistake my statement as an exaggeration. If you don't like Metroid and never have, you probably never will; Zero Mission won't change that. But if you're like most of us and think this is one of gaming's best franchises, Zero Mission will expertly massage every "must...keep...upgrading" nerve in your brain and throw all kinds of surprises at veteran players. It takes all the best features and ideas from the entire Metroid series, along with some significant new elements, and applies them to the game that started it all, which was becoming quite outdated, despite its many revolutionary gameplay concepts. Yet it seems like the designers went overboard, recreating the game so thoroughly and adding so much new gameplay that it's nearly unrecognizable as a makeover of an old game. So please, turn away now if you want a simple audio-visual upgrade to the classic. Zero Mission looks and feels like an entirely new game, in a series that lacked sequels for such a painfully long time.
The story of bounty hunter Samus Aran's infiltration of the Space Pirate base on Planet Zebes is well-worn by now, and Zero Mission adds little more than a few background details until its radical appendix near the end. Your mission, which is still told primarily through environmental clues and not by text or even cut-scenes, is simply to dig into the heart of Zebes and destroy Mother Brain, her army of Space Pirates, and the Metroid creatures being experimented on. How you accomplish this task is seemingly wide open, as the game appears to be extremely non-linear and heavy on raw exploration. (Seasoned Metroid fans will know that the game actually has you on a fairly strict path, but it hides the intended sequence in a maze of upgrades and...mazes.) Newly added Chozo statues give hints for where to go next, but their directions are quite vague. More useful is the newly added auto-map function from the later games, including map stations which download data for entire regions. The art design itself makes navigation easier than in the original game, since you no longer move from one identical vertical shaft to another, not quite sure where you are or where you're going or if you've already been there.
I feel like I'd be spoiling the experience if I talked much more about the game progression or the upgrade sequence. Suffice it to say that there are many powers and techniques from other games in the series, and there are several new bosses and areas on the map. Zebes is much larger than in the original game, now about the size of Super Metroid's version of the planet. New gameplay elements include ceiling zip-lines and morph ball launchers, neither requiring any new abilities to use. The ability to hang on ledges and pull up into tight spaces is back from Metroid Fusion, but this time it has to be earned as a separate upgrade. The classic bomb jump technique has been brought back as well, and it can now be used practically infinitely if your rhythm is good enough. In fact, the timing for bomb jumps seems to be more forgiving than ever before, and a quick mastery of the move allows for several sequence-breaking moments (i.e. getting an upgrade or accessing an area before the game expects you to). There are a multitude of new gameplay elements thrown in near the end of the game, but I couldn't describe them without ruining one of the best surprises this series has ever seen. Just rest assured that it's awesome, and it feels completely different, yet still natural and very, very exciting. (My heart was racing!) Metroid fans will be shocked out of their gourds, if they've managed to avoid spoilers up to that point.
New content aside, Zero Mission is obviously a tremendous audio-visual upgrade over the original Metroid. The included emulation of the original version is a great bonus, if only as a reference for comparison. Every single piece of art has been redone, with most sprites now considerably larger than before. The environment proportions, however, seem to have been left alone, making the caverns of Zebes feel more intimate and, arguably, more claustrophobic this time around. The unforgettable, seemingly never-ending vertical shafts have been contracted quite a bit, and the platform and color schemes are more varied in the remake. Zero Mission also features a remixed soundtrack. There are more and better instruments, as you'd expect, but none of the tracks have been rewritten with drastic changes. The result sounds more like a polishing than a recreation. I still prefer the original title theme, as it's not as muffled as the new one, and because the original MIDI instruments just worked perfectly for that arrangement. Most sound effects have been replaced with ones from later games, and there are unfortunately not many new sounds to listen for. The game avoids voice-acting altogether, and rightly so.
Length is always an issue when a new Metroid game is released. Zero Mission is not the longest in the series (that title would probably go to Metroid Prime), but it's longer than Fusion and almost as big as Super Metroid. Your playing time on the first run will depend heavily on your all-purpose Metroid skills, whether you played the original version (and thus have some familiarity with the maps), and how much you care to look for secret items. My first run was about six and a half hours with 80% of the items, and I am a pretty good Metroid player as well as a veteran of the original game. It all depends very much on your playing style. In any case, there's just no way to argue that this is a long game. It's not. Neither are any of the other Metroid games. The first one you play always takes a while, but once you get the hang of moving Samus and a feel for how the levels are designed, you can blow through even a new game with ease. However, Zero Mission does a good job of extending its value, with an unlockable Hard mode that will challenge any Metroid fan, as well as hidden art galleries that open up as you beat the game with fast times and high item completion rates. Some of the hidden items are also truly devious, which will keep completists busy for some time. Being that most of us will play through it at least twice, it's not hard for me to recommend Zero Mission as a purchase. I didn't feel cheated with Fusion, and this game is longer with more reasons to go back and play some more.
So pick it up and have a blast. This isn't just Metroid...this is THE Metroid, an impeccable "remake" that might as well be a completely new game. It's probably my favorite in the whole series, and that's saying something.