Back at the research facility, which seems to be where the Subspace transport was heading, Samus and Pikachu are finding their way around the facility to get to Samus' power suit.
A dark room
Go right and defeat the enemies in your way. This room will mostly be shrouded in darkness, so keep going forward until you reach a switch, which you can attack to light the room temporarily. Be sure to watch out for any other similar switches, as you're basically blind when wandering around in the darkness. Clear the blocks in front of you then go past the formation of R.O.B. Blasters. You will reach another light switch, which is convenient as the room will turn dark again not long after.
In the hallway below the switch is the first appearances of Glices. Like the Glires and Glunders from before, they attack if you get too close, but their icy attacks will actually freeze you in place. You can escape from being frozen early by rapidly moving in all directions. After the Glices are two switch-activated walls that can block your path or crush you in between. They close when the room is light, so wait until the room goes darj to pass through..
There is another light switch, but this one will actually spawn two Big Primids, so try to avoid it if you can. There is another light switch close by that doesn't spawn enemies but cause the red walls to move, so attack them instead. Go between the red walls when they stop moving until you reach a dead end, then wait for the screen to go dark again to proceed. The next light switch is at the right end of the room, patrolled by some enemies. You don't need to fight them, so you can go straight down the ladder.
If you manage to reach the bottom before the room goes dark again, you can enter a secret door on top of some red platforms. The blue and gold item boxes inside are easily within reach, so collect your bounty and exit the room. Back outside, jump up and go to the right to reach a door. Beyond it is a short hallway filled with enemies. You can choose to fight them or run past them, but your goal is to reach the door at the end of the hallway. Enter it to trigger a cutscene.
Samus and Pikachu finally reach the chamber with the power suit, but it turns out to be a trap! The walkway they came in on retracts behind them, as two fake Samuses made off Shadow Bugs approach and fight them, fully armed with their own power suits. If Samus is going to retrieve the actual power suit, she will have to fight her malevolent doppelgangers for it.
False Samus fight
You must now fight two Samuses at once, which can be a bit difficult if you're playing alone. The stage you're fighting on is totally flat and fairly large, which can make KOs take longer. Fortunately, the fake Samuses appear to be a bit lighter than the real deal. Take on one Samus at a time, keeping both separated to prevent them from ganging up on you, then keep switching between fighting one Samus and the other until you can KO one of them and focus exclusively on the other.
An alarm sounds and R.O.B.s pour into the room, but are blasted away by a single shot. Samus has put on her power suit and is fully-equipped for battle. Now she and Pikachu must make their escape from the research facility.
The first part of this area is a straightforward hallway with a few enemies. Go right until you reach a large wall of blocks. You want to carefully break the blocks to reach a hidden trophy in the lower left corner of the pile of blocks. After that, break apart the remaining blocks preventing you from going right. In the following room, there will be spiked on both the ceiling and the floor, and you must jump on to the moving platforms and off them before they push you into the spiky ceiling. You can attack the switch to stop them temporarily, but you can safely ignore them if you're fast enough.
After that is a similar series of platforms, but instead of a spiked floor there is a bottom less pit. Be careful when jumping across the platforms and feel free to stop the platforms to safely cross the chasm. Watch out for the R.O.B. Blaster as you reach the last platform, as it is difficult to dodge their rockets without hitting the spikes on the ceiling. The door is not far ahead.
Move forward and attack the switch to cause a platform to appear. Jump on it to have it carry you along the green track. Jump off as soon as you go past a high ledge, then jump to the next platform and attack the button there. Ride the elevator until you reach a forced battle. After the battle, attack the nearest switch and ride the elevator it creates. Jump off at the first lower ledge you pass, then attack the bomb blocks to reveal a door to the left. Enter it.
Inside is a pair of potato masher-like platforms that quickly bounce between the floor and the ceiling. Attacking the switch will stop the platforms temporarily. You should stop the first platform near the ceiling to pass underneath it, then stop the next platform as low as possible to jump over it. The gold item box in on the other side, but you still have to go back to the right side of the room to exit. Exit and climb to the top of the ladder, then attack the switch to make the platform appear again.
Ride the platform down, then jump to the left platform once you pass between two of them. Ride it until it nearly passes the top, then jump to the left platform. Ride that platform down and jump to the first platform you pass by. Ride it to the right until you come across a ledge with a door. Go through it to reach the next area.
Portals on the floor
The door is within sight, but a red gate stands between it and you. There are portals in the ground that take you to other sections of the level. First, you want to go through the lower portal to reach a forced battle with a Roturret and some Primids. Defeat them, then go through the right portal after the battle. After that, you must jump to the very top of the room you end up in to reach the portal at the highest alcove. In the next room, ride the platform to the very left, skipping the portal in the middle, and go through the portal at the very end.
You will end up in a different section of the room you arrived in. Go right and attack the switch to retract the red gate, then go back through the portal. Back on the moving platform, jump on to the platform with the middle portal, which will take you to a room with a gold item box. Get it, then go through the portal nearby to return back at where you started. Go through the now accessible door to enter the next area. In the following hallway, you can break apart the blue item box to find some healing items, then go through the door to trigger a cutscene.
Samus and Pikachu find themselves in a huge cylindrical room. Suddenly, Ridley, Samus's arch-nemesis, swoops in and grabs Samus. He flies up high and slams her into the wall, then drags her helplessly along the walls of the room. Pikachu quickly uses Thunder to strike Ridley, forcing him to drop Samus back down to the platform. Ridley is still alive despite this, and both fighters must defeat this monstrous pterodactyl if they wish to escape.
Boss Battle: Ridley
Ridley is fairly large, similar to the other bosses, but it is a bit harder to hit as it constantly hovers above the side of the stage, meaning that most ground moves have trouble hitting him. Ridley also follows a set attack pattern, and knowledge about this pattern will help you tremendously when anticipating his moves. For his first attack, Ridley can either scrape the floor with his tail, perform a loop or fly offscreen and rush at your current level. The tail attack can be dodged simply by jumping above the sparks, while the loop and the charge both require a well-timed air dodge.
For his second move, Ridley can also perform his tail scrape. Other than that, he can blow a strong wind that pushes you back or sweeps across the floor to the other side. The wind is mostly harmless if you're not touching him when it starts, while jumping and dodging should let you evade his sweep attack. Ridley's third and final attack in his set pattern all involve landing on the stage and leaping offscreen. He will then slam back down to the ground or fly at you from the back of the stage. The ground pound can be dodged by simply running far from where he jumped, while the rush from the back can be dodged by jumping up high as he passes you.
Having defeated Ridley, Samus and Pikachu emerge from the research facility to find themselves in a verdant field littered with ruins. Samus spots a pair of R.O.B.s carrying a Subspace Bomb out from an underground entrance. Recognizing the bomb as a weapon that has caused a lot of chaos lately, Samus decides to investigate the rest of the island, with Pikachu tagging along with her.
Samus, now fully armed with her power suit, will now join your team!