Let's just get this out of the way up front: Metroid Fusion is an imperfect follow up to what many consider the best game in the Metroid series, Super Metroid. It's a good game, no doubt, and fun in its own way, with attempts to do things different from what came before (so we're at least not getting the same game all over again), but it's not as good as the previous title. That's the big knock against it, but when you're trying to follow up Super Metroid how are you ever going to be as good.
Well, okay, some would consider Metroid Prime to be a near perfect follow up to the near perfect Super Metroid, but we're not covering the Prime games on this site and this article is supposed to be about Fusion and we've already forgotten what we were talking about.
Right, yes: Metroid Fusion. Following the events of Super Metroid, our heroine, Samus Aran, has been critically injured after returning to Planet SR388, site of her Metroid extermination mission (back in Metroid II). She was attacked by X-Parasites, creatures whose only known predator were metroids (which, as you will recall, were wiped out by Samus, so that wasn't such a great plan after all). To save Samus the scientists have to infuse her with metroid DNA, thus giving us the "fusion" of the title. Suddenly, there's a problem on the starbase orbiting SR388 and the X-Parasites that were being studied there have gotten out. The only person that can possibly go there is Samus since, fused with metroid DNA, she's now resistant to their attacks.
Credit where it's due, Fusion has a compelling concept. Fusing our heroin with the DNA of what is, arguably, her long-term nemesis is an interesting twist. Having the plot be essentially a problem of her own making is also pretty fascinating -- if she hadn't gone to the planet and killed all the metroids, she wouldn't be in this mess now. That's a really interesting re-exploration of the series's overarching plot.
Really, the problem with the game isn't a thin story. One of the biggest issues, in fact, may be too much story. If you've played any of the Metroid games that came before, you'll know that Samus is a lone heroine. When she goes somewhere to fulfill her mission, she's set there until she's done. She doesn't leave, and she doesn't have anyone to talk to. What she does on the planet is her business, and she gets to do it any way she sees fit. Fusion, though, forces a narrative upon Samus. She has to complete parts of her mission in a specific order, and the whole time she's getting orders from (and participating in cut scenes with) and off screen character (we're lead to assume it's an A.I. before more story reveals just what the character is or who it may be). We've never needed story like this before, so it's a mystery why Nintendo felt like it was needed here.
Actually, we can assume why story like this was put into the game, but we'll discuss that further below.
Instead, let's discuss the other big change to the formula: segmented, forced missions. As noted, Samus has to do things in a certain order to complete the game. You want to go here, well you have to turn the heat off in the leve section of the space base, then maybe venture over to the water section and turn off the power before entering the heart section and saving Captain Planet. While we're being sarcastic about it, we're really not far off: there are six sectors of starbase representing six ecologies, essentially allowing the game to give us all the usual terrains, from ocean to ice to lava, all on a spacebase. It's weird. And because of the mini-missions you have to complete in each area, you don't get to play the game in classic, non-linear fashion. This may, in fact, be the most linear Metroid game in the series (certainly the most linear 2D game, for sure).
Which again brings us back to why? Why was the game so segemented, with such an emphasis on story over exploration?
Similarities to Castevania Games
Let's call it the Castlevania-fication of Metroid. No game takes place in a vacuum, and while the previous Metroid games simply got to expand and comment upon themselves, with the release of Castlevania: Symphony of the Night, another franchise had entered into the Metroidvania genre and done it well. Now, this is just theory on our part, sure, but it's hard not to see the evidence of Castlevania's influence on the Metroid series.
For starters, let's look at the story of Metroid Fusion. Samus is regularly interacting with an A.I. named Adam. He tells her what the mission is, where to go, and passes her powerups to use along the way. This is a lot of new story elements to include in the follow up to Super Metroid. And yet, look at the interaction between Alucard and Maria in Symphony or Juste and Maxim in Aria of Sorrow. We certainly didn't need Alucard to be regularly accosted by a blond woman every 15 minutes or so, but it did help to break up the action, and it allowed him to brood (and ALucard is fantastic at brooding).
Similarly, we don't need the Samus to be accosted every few minutes by an A.I., but that's what other games in the genre were doing, so now we get it in Fusion.
Similarly, why break up the game into mini-missions that have to be completed? Because story takes a front seat over exploration. Alucard has to learn how to safely defeat Richter to save the day. Juste has to figure out what's going on in the two castles so he can stop Dracula and save Maxim. Samus has to be told what to do in each ection of teh starbase before it all explodes and she dies. This is the genre now, and that includes the Metroid games, for good or ill.
For all our grousing, don't think we hate Metroid Fusion. It's a very fun game and it does things differently from the previous titles. It just so happens that what it changes makes the game feel much less like a Metroid game and much more like a Castlevania game. And we love Castlevania (obviously). We just don't need that much of it in our Metroid games.