Once you get a handle on some of Metroid Fusion‘s mechanics beyond “run/jump/shoot,” you also get a little lesson in reading its map to find secrets.

In a game from the cartridge era, where no pixel of space existed without good cause, this empty room should pique your curiosity. It seems to be a dead end with no real value, just an empty chamber leading to an oddly stair-stepped wall with no standout features. However, if you look up at the minimap in the upper right corner, which has been filling out details as you travel through rooms, you’ll notice this particular room (the current room or screen always sits at the center space of the minimap’s 3×3 grid) has a circular icon in it. Rooms where you’ve collected a pickup are always marked with a dot, but the circle denotes an unclaimed pickup. You can’t see a pickup at a glance here, but Metroid vets know the drill:

Sometimes, you have to shoot the scenery to make secrets appear. You’ve already seen how dynamic bricks can be disguised as normal scenery (such as the crumbling blocks that led you here), and you’ve been forced to explore shooting up the walls in order exit the observation deck. This room combines those two features for a new purpose: Hiding a collectible. In this case, another missile.

Something that only now occurs to me is that playing this game on the Wii U’s Game Pad or a nice TV doesn’t really convey the intended effect of the graphical design. Remember that the original Game Boy Advance was kind of a piece of garbage where its screen was concerned. When Fusion debuted, the side-lit GBA SP was still several months away. The game was designed to be played on a dim, unlit screen, and on its original platform the obscured areas outside of Samus’ immediate range of vision was essentially black. On today’s better screens, you can pretty easily see threats and details in shadow, but the original intent really was to leave you in the dark in a very literal sense.

Anyway, here’s a dude you probably remember from Super Metroid: The crazy eyeball monster who takes up residence on boss doors. This apparently is a Metroid thing now, even if it doesn’t precisely make sense given that you only encountered these on Zebes in the Space Pirate base and the X parasites in the BSL station are mimicking creatures from SR388. But whatever. You can only hurt this and open the passage it blocks with missiles (the red color is your clue) when it opens its eye… except when the eye opens covered with a yellow film, which means it’s going to fire a Samus-sized energy beam at you. A few hits will open the oculus rift, simultaneously loosing a red X parasite at you.

There’s an added element of danger here as well: Even if you destroy the scientist zombies wandering around and collect their X parasites, a moment later more parasites will swoop in and revive the creatures. Like Shandor Building in Ghostbusters, this region (as Adam indicated) is a hotbed of paranormal activity. The constant influx of X is nice in that it means you’re constantly able to restore your health and missiles in the event you take a hit from the eye creature’s beam (or from zombies while dodging the beam), but it also means there’s no time to rest here, either.

With the eye thing destroyed, you pass through another service conduit where an Energy Tank is simply sitting, waiting for you. Previous games may have taught you to distrust Energy Tanks waiting in the open, but there’s no trick here. You simply grab a can’t-miss tank to double your maximum health, much needed…

…just in time to take on the first boss, which appears as an advanced X. It sweeps in, gathering smaller parasites, eventually coalescing into its “true” form.

But first, let’s look at the room itself. Technically, this room isn’t shut off: You drop in from the top, which doesn’t seal shut behind you. And there’s a small opening in the wall at the bottom left that you could potentially pass through if only Metroid could crawl. But you can’t, so effectively you’re trapped despite the theoretical freedom to exit.

Also of note are the small recesses on either wall. You can’t climb into these, but you can cling to them for safety.

Which it turns out is a good idea, because this boss is much more difficult than you might expect. Fusion differs from previous Metroid games in that the combat is much faster-paced, enemies more aggressive, and their damage output much higher as a result of Samus’ newfound weakness. Compared to the first battle in Super Metroid, the Torizo statue, Arachnus here uses more and more frequent attacks and hits much harder.

You should, of course, recognize Arachnus: He’s a larger, more dangerous version of an optional boss from Metroid II. “Well, of course,” you say. “Fusion‘s all about riffing on Metroid II.”

But this is not an incidental or spurious reference! Arachnus has an interesting place in Metroid history, as it was the first boss you battled to gain a power-up directly rather than from a Chozo statue (the creature disguised itself as a Chozo item orb). This would be echoed in the Torizo bosses in the sequel, but nevertheless Arachnus has a special and unique place in the series’ design, and makes for a fitting cameo here: You won’t be gaining powers from Chozo artifacts but rather by defeating X parasites that have siphoned away Samus’ abilities, and so it’s perfectly fitting that the first boss in this new schematic calls back to the first time you experienced this break from tradition.

That said, Arachnus is way harder this time around. Before he just kind of rolled back and forth, popping up and waving his mouth claw at you. Now he creates a shockwave that travels quickly across the floor, moving back and forth to crowd you into corners.

He can also create a massive blaze of fire that travels forward across the ground and lingers for several seconds — you can jump over the shockwave easily, but the fire can’t simply be waited out with a single jump. You either need to leap over to Arachnus’ backside or else hang from the recesses until the flame gutters out.

Likewise, you can’t fight Arachnus (or Arachnus X) the way you did in Metroid II; you had to bomb it to death there, which is impossible here as you don’t have a Morph Ball or Bombs. So instead you just pepper it with missiles in its face — and, reminiscent of more evolved metroids on SR388, its carapace is invulnerable, so you have to blast its moist, tender underbelly. The creature doesn’t make it easy, but fortunately those “free radical” parasites drop in occasionally to allow you to stock up on health and missiles.

Once Arachnus-X has been stomped, it reverts to its primal form, a floating super-parasite with trailing subordinates. The big parasite shell can’t be absorbed — the spikes should make it clear that it’s dangerous to the touch — but its little ones can. You need to smash it open with missiles.

Once you’ve cracked its bitter shell, the gooey morsel inside floats helpless and free for you to absorb.

Your gift is the ability to tuck into a tiny ball and roll about, allowing you to squeeze through the small opening to the left and return to the main station spaces.

Whereupon you can blow up that stupid gummy door obstruction, which no doubt has been antagonizing you since you first encountered it. Equipped now with missiles and the ability to roll into small spaces, Samus is a little less likely to die horribly now. The theme of Fusion remains “Samus is weak,” but that slowly changes as you advance.