Metroid Fusion is an action-adventure video game published by Nintendo for the Game Boy Advance. It was released in North America, Europe, and Australia in November 2002, and in Japan in February 2003. The game is considered to be the fourth main installment in the Metroid series; the intro alternatively refers to the game as Metroid 4. Metroid Fusion was developed by the same development team that created the previous Super Metroid, to which Metroid Fusion bears heavy resemblance.Chronologically, Metroid Fusion takes place last in the fictional Metroid universe. The story centers around bounty hunter Samus Aran, who is sent by the Galactic Federation to assist Biologic Space Laboratories in their expeditions on the planet SR-388, which Samus had purged of Metroids in Metroid II: Return of Samus. While defending the scientists from the local wildlife, she gets infected by a previously undocumented gelatinous lifeform and later passes out while piloting her gunship. The organism has spread throughout her body and her biomechanical Power Suit, and the scientists surgically remove portions of the infected suit to no avail. In a last ditch effort, the scientists infuse Samus with a serum containing preserved Metroid DNA, which destroys the parasite and cures Samus.Now sporting much-altered armor, Samus is sent to the BSL space station to investigate an explosion. There, she learns that the station is swarming with organisms infected by more of the gelatinous lifeforms — now called X Parasites — virions that can replicate their hosts' physical appearances and memories, killing them afterward. The fact that the Metroid DNA saved her and allows her to absorb other X Parasites is now known to be because the Metroids, genetically engineered creations of the Chozo, were made to be predators of the X; the recent Metroid purge let them infect the creatures on SR-388 and spread once more. In order to check the spread of the infestation, Samus must work her way through the station under the guidance of her new gunship's Artificial Intelligence and eradicate the X Parasites and their host bodies, among them the SA-X, a clone produced from the remains of her Power Suit.The game is notable for having a much more in-depth plot than the previous games in the series, full of political and corporate intrigue and character interaction. While the first Metroid Prime game, released the same year, opted to tell its story primarily through scan logs, Fusion tells its story through dialogue with the above-mentioned AI and through Samus' Internal Monologue. As a result of this heavier emphasis on story, the game is more linear than the previous games as well.The game can be hooked up to Metroid Prime to unlock both Metroid 1 and a Fusion Suit skin for Prime.
After Boss Recovery: Justified, as all the bosses and enemies are made of X Parasites that Samus absorbs to recover health, so it makes sense that the bigger bosses have more potent X for her to eat.
A.I. Is a Crapshoot: Ultimately subverted with Adam. At about the point one might expect him to start singing "Daisy Bell", he sides with Samus against the Federation and helps her destroy the X Parasites. Adding to the subversion is the fact that Adam's not a true AI either; he was human to begin with, and just had his mind uploaded before he died.
All There in the Manual: The games are easy to understand plotwise on their own, but there's quite a bit of canonical backstory for both Zero Mission and Fusion, as well as the entire franchise on the whole, to be found in the manuals and the two-volumemanga.
Asteroid Thicket: During the opening, Samus' ship crashes into one of those. The asteroids look like they're only a few hundred feet across, and tightly packed.
Bag of Spilling: Played with. Samus kept all of the weapon upgrades to her power armor. Unfortunately, her power armor was infected with a parasite which is now using all of those weapon upgrades to try to kill her.
Beauty Is Never Tarnished: Parts of Samus' suit have to be surgically removed, but not all of it could be taken off. This is due to much of her suit "fusing" with her central nervous system. She is given Metroid DNA to counteract the X parasite. This, along with her Chozo DNA, does not seem to affect her appearance in her death animation, though. It is also unclear whether or not she can ever remove her suit by choice.
Book Ends: The game provides three. The end to the original trilogy had the super metroid heals and gives you a weapon to defeat the final boss, saving your life. In this game, the Metroid's DNA cures Samus of the X-Parasite infection (saving her life), and makes her able to absorb the X to heal her and replenish her supplies (giving her the weapon to eradicate the X). Also the ending, in which the SA-X, saves your life, heals you, and gives you the weapon to eradicate the Omega Metroid. Also, both the very first boss (Arachnus) and very last boss (Omega Metroid) are from Metroid 2.
Breaking the Fourth Wall: A hidden Easter Egg lets Samus sequence break to skip an area to another save station. Doing so will cause Adam and a mysterious figure to congratulate her, with Adam musing "I wonder how many players will see this message?"
The Cavalry: Samus had beaten SA-X, plotted the B.S.L. Station on a collision course with SR-388, and was on her way to her ship to escape. But when she gets to the docking bays, the place is a mess, her ship is missing, and there is a huge shedded skin on the floor. Suddenly, an Omega Metroid comes in and screeches at Samus. With one claw swipe, Samus is knocked down to one HP and immobilized. Before the Metroid could kill her, the SA-X appears and blasts its chest with the Ice Beam, but it is defeated by it. However, Samus absorbs its Core-X, which restored her Ice Beam ability, and proceeded to blast the Metroid to dust.
Chekhov's Gunman: The Etecoons and Dachoras from Super come back in this game, and this time THEY save you. After needing saving a second time, but still.
Chest Monster: One of the X-Cores impersonates a Chozo Statue (most likely a Torizo, considering hosts need to be organic).
There are also traditional chest monsters. There is at least one hostile Energy Tank and a Missle Tank mimic in the game with the real one sitting in the room behind it.
Climax Boss: Nightmare. Especially after playing Other M.
Color-Coded for Your Convenience: The doors are color-coded by security-clearance. Samus needs to find the override controls for each security level to unlock them. This becomes a plot point, as unlocking the controls also allows the X-parasites to spread further through the station.
Continuity Snarl: The way Samus' suit works in this game (particularly how it functions when Samus in unconscious) is very contradictory to other games, especially Other M.
Cool Starship: Samus' gunship, natch. The loaner ship she gets from the Federation after totaling her own in the opening may count as well.
The Dev Team Thinks of Everything: After getting the Varia suit back, the formerly harmful blue X become harmless like all the other types, but the X (who intentionally suicide bombed you to weaken you) don't know that yet, so rather than immediately starting to run away, the first few blue X you find will continue to suicide bomb you, only running once they see it's stopped working.
You can even keep on purposely avoiding the Blue X to prolong the time it takes for them to stop the kamikaze attacks.
Through a sequence of shine-sparking, it is possible to make it back to the Naviagtion Room at the beginning of Sector 4 after defeating Nightmare without going the long way and getting the Diffusion Missiles. Adam and the unknown Federation member do have something about this.
Fake Difficulty: Compared to the other Metroid games, the game seems to unfortunately suffer the most from this: despite the fact that the maximum energy tank count is far higher than in the other games of the series, Samus takes by far the most damage per hit even with all the defensive upgrades unlocked and the amount of health given by the X parasites never increases during the game, not to mention the fact that chasing them down is more than likely to get you hit again by other enemies and they can easily form into another enemy you need to kill before you have a chance to absorb them if the game's feeling sadistic. Sure, there are recovery stations in every section of the station, but they're almost all placed near the main entrance of the section which doesn't help you much when the boss is on the other side of the map and the nearest savepoint might still be several rooms away.
Foreshadowing: Remember how in Metroid II, Samus was sent to SR-388 to dispatch all Metroids? Including some in deep nocturnal areas of the planet? Is it any coincidence that Sector 1 (SRX), a section designed to replicate the environment of SR-388 completely, is located right next to Sector 6 (NOC), a place meant for housing nocturnal creatures? What could be between them? A restricted laboratory, involving the breeding of Metroids, perhaps?
From a Single Cell: X-Parasites, if not absorbed, will simply reform into another body. Also, the Federation had preserved a Metroid cell culture from the Metroid Hatchling. A vaccine made from these Metroid cells was used to cure Samus when she was infected by an X in the game's intro.
And they also used it to grow new Metroids in a restricted laboratory hidden on the B.S.L Station. Apparently for peaceful applications only, after what happened in Other M.
Heroic Sacrifice: Samus almost attempts one by detonating the self-destruct charges on BS-L to destroy the X-Parasites aboard; herself included. The AI Adam, however, informs her that doing that would be stupid, as it would not destroy the X on Planet SR388, and only serve to destroy the X's greatest obstacle: Samus. A different plan is then created, which destroys all the X in both locations and allows Samus time enough to escape the station.
High Voltage Death: Electrified water is a hazard in the third zone you visit where you get the Speed Boost; that damages you over time. The player can accidentally kill themselves falling into it if they have low health.
Hopeless Boss Fight: Every SA-X encounter before the proper boss battle in the finale. You have to either evade or escape it.
Monster Delay: Nightmare is introduced as it streaks across the now wrecked sector of the ship. Mission Control tells Samus to ignore it for now, so she continues on. Later, the AI realizes how much damage it has caused and tells Samus to destroy it.
Nice Job Breaking It, Hero: Samus' Metroid extermination campaign caused an explosion in the population of the X Parasites, which the Metroids had been designed to kill. Oops.
Plug 'n' Play Technology: The Fusion Suit is able to form new abilities just by absorbing "data" acquired from rooms and the DNA of the X parasites.
Point of No Return: Once you go up to the main deck to alter the station's trajectory, every possible route back to the various sectors is sealed off. Your only option left is to finish the game. Except in New Game+, which does not seal off the sectors until the final evacuation countdown.
Recurring Boss: The SA-X, which appears to stalk you every now and then, though it's not really a boss until near the end of the game.
Run or Die: This is the only advice Adam gives Samus regarding SA-X at the beginning, because it's equipped with all of Samus's weapons and abilities, including the Ice Beam which Samus is now weak against due to the Metroid Vaccine.
Sequel Hook: Fusion sure seemed to leave one hell of a sequel hook, what with Samus having illegally blown up a Federation outpost and become something way other than human. Sure, Samus had her reasons, but all the implications in-game are that the Fed will be pissed as shit with her now.
Something Only They Would Say: How Samus discovers that her AI CO, which she nicknamed Adam, after her old CO Adam Malkovich, actually is Adam Malkovich.
Suicidal Overconfidence: The first few free-floating X Parasites encountered will attempt to infect Samus again, not knowing she's now part-Metroid and can eat them on contact. They learn to avoid her quickly, but it takes another lesson for the cold X Parasites after Samus regains the Varia suit.
Survival Horror: Metroid Fusion will never be confused with Silent Hill 2, but the claustrophobic environment, the strictly linear gameplay, the profusion of locked doors, and the relentless pursuit by an invincible enemy give the two games an uncanny resemblance.