The Underpass Resonant Walkthrough in CONTROL Resonant

The Underpass Resonant quest in CONTROL Resonant takes Dylan to the top of The Spire and then into the Astral Plane, where three locked doors block the path to the local Resonant. Each one requires a separate Astral Key. In this guide, we'll explain how to complete the quest, find all three keys, and defeat The Physicist.

How to Climb The Spire

Head to The Spire in the Underpass and start climbing, using Shift to move across vertical surfaces.At the top, you'll face three waves of Hiss enemies, including a miniboss. Since the fight takes place on a vertical surface, you can knock enemies over the edge. It's best to deal with ranged attackers first, then focus on the more dangerous melee enemies.After the fight, go through the square opening and Shift planes near the edge. This will take you farther along the route.

How to Reach the Astral Plane

At the top of The Spire, Dylan will enter the Astral Plane, where floating platforms hang above an endless white void.Climb onto the first platform ahead, then perform a double-dash jump to reach the opposite side. Just before you fall, use Shift to latch onto the surface.Keep climbing the structure. At the very end of the path, you'll find a set of large locked doors. To continue, you need to find three Astral Keys.

Where to Find the First Astral Key

From the locked door, jump down onto the lower platforms to the left and follow the route until you reach a chest. Interacting with it causes three geometric enemies to appear. They will chase Dylan and try to ram into him.Destroy all three, then head left and interact with the next chest on the ground. Spikes will begin rising from the floor.Head right and find a wall you can climb using Shift. Continue past the desks and office equipment. At the end of the route, you'll find a glass display case containing the first Astral Key.Take it and return to the locked door. Behind it, you'll find another locked passage.

Where to Find the Second Astral Key

From the second door, turn around and follow the platform all the way to the end. Jump across the gap and head toward the checkpoint marker. As you approach it, three more geometric enemies will appear.After the fight, cross the next gap and turn left. Near another checkpoint marker, spikes will start emerging from the ground. Wait until they fully retract, then climb up the wall.Jump across the gap, head left, and climb the cubes on the right. Cross another gap, then use Shift to continue along the walls until Dylan is completely upside down.Turn 180 degrees and look for another platform with a glass display case. The second Astral Key is inside.Return to the door, unlock it, and get ready to search for the third key.

Where to Find the Third Astral Key

From the third locked door, turn around and jump down onto the platform to the left. Cross the gap and follow the path until you reach a chest.As you approach it, the chest will disappear and reappear on the next platform. Keep following it until it appears on the wall to the left. Jump across the gap and use Shift to continue along the wall.Follow the chest until you can finally interact with it. Another group of enemies will appear. Take them out, then head toward the far-right corner of the area.The path leads to the final glass display case containing the third Astral Key. There are also four chests nearby containing upgrade materials.Take the key, return to the final door, and unlock the passage leading to The Physicist.

How to Beat The Physicist

The Physicist uses area-of-effect attacks, projectiles, and spikes, and the fight takes place across several arenas.

Phase One

As soon as the fight begins, create some distance. The Physicist will chase Dylan and trigger a powerful area-of-effect explosion whenever it gets close. The boss repeats this attack several times before rising into the air.From above, it fires three volleys of four projectiles. Run in a wide circle around the arena to avoid them.After returning to the ground, The Physicist performs a circular attack around itself. Jump and attack the boss from the air to stay outside the damage zone.When The Physicist starts charging another explosion, wait for it to detonate, quickly close the distance, land around three hits, and immediately retreat. Don't extend the combo or you won't have enough time to escape the next attack.Keep repeating this strategy until the boss rises into the air and starts destroying the current arena. Then follow the newly opened path.

Phase Two

On the next circular platform, The Physicist will split into four smaller copies. Destroy them one at a time, since taking several hits in quick succession can leave Dylan stunned for a long time.Once all the copies are destroyed, The Physicist will reform. It keeps its previous attacks but gains two new ones.For the first, the boss moves away and sends several waves of spikes across the ground. Dodge left or right while gradually closing the distance so you can attack as soon as the move ends.For the second, The Physicist releases a pulse that causes spikes to erupt directly beneath Dylan. You can still land a few hits during this attack, but as soon as you see the pulse charging, dash to the side.Once the boss is down to roughly half health, it will move to the next arena.

Final Phase

In the final arena, The Physicist summons two spherical enemies while continuing to attack on its own.Destroy the spheres first. If you leave them alive, they'll make it harder to dodge the boss's attacks and can stun Dylan with several consecutive hits.After that, focus on The Physicist again. It won't gain any new attacks. Use the same openings after its explosions, circular attack, and spike attacks until you finish the fight.

Quest Completion Reward

After defeating The Physicist, you can choose one of two combat abilities:

• Spike;
• Astral Rebuke.

This completes The Underpass Resonant quest.