Where To Find All Three Astral Keys In Control Resonant

Published Sep 22, 2026, 11:00 AM EDT Collin is a Guides Staff Writer at TheGamer who has been writing guides for nearly ten years. He is also a professional game/level designer. More importantly, he's still waiting for a new Ape Escape game to release. Control Resonant has a ton of things that are trying to rip you to shreds. From the Hiss to the Mold-infested enemies, you'll come across quite a few horrors when exploring New York City. Some of the toughest enemies in the game are Resonants, which act as Control Resonant's main bosses. With one per region, these will act as skill checks to see if you've mastered the game's combat systems. One of the later Resonants is The Physicist, which can be found in The Underpass. Here is where to find all three keys to unlock the boss room and how to defeat this enemy. The Underpass Resonant Walkthrough See Where The Spire Leads The first step of this boss quest will task you with scaling the spire in The Underpass. Use your Gravity Anomaly ability to run up the wall until you reach an area that's guarded by Hiss enemies. You'll face three waves of Hiss, including a mini-boss variant of the Hiss Pursuer. Focus on the Hiss Freighters first, as their ranged attacks can be quite deadly and difficult to dodge if you're battling other enemies. Since you're technically fighting on a wall, consider knocking enemies off the edge, as it will send them plummeting into the bottomless void below. Eskil, the mini-boss, is quite tanky, so make sure you have a Blunt damage weapon to ensure you can punch through his armor. If you want, this will be a much more frustrating fight since he is highly mobile and can easily cut you to pieces. Once all the enemies have been defeated, go through the square hole, and shift your plane once you reach the edge. Investigate The Astral Plane When you reach the top of the spire, you'll arrive at the Astral Plane, which is just more floating platforms in an endless white void. Make your way up the first platform in front of you and then perform a double dash jump to reach the other side. You'll need to shift planes when you're close to save yourself from falling. Climb this tower and, once you reach the top, run to the very end where a pair of locked double doors are. Find The Key And Unlock The Door After interacting with the door, you will learn it's locked and that you need to find a key. Start by heading left from the door by jumping down to the lower floating platforms. Follow the path until you reach an area with a chest. Interacting with it will spawn three geometric orbs that will follow you around and attack. These enemies can do a decent amount of damage, but their only move is to ram themselves into you. Destroy all three, head left, and interact with the next chest on the ground. Doing so will cause spikes from the ground to appear and sweep across the ground. Head to the right to find another wall you can run up with Gravity Anomaly. Following this trail of desks and office equipment to the end to find the Astral Key in a glass box. There will also be an audio recording and a file on the desks along the left side. Bring the key back to the locked door to discover there's a second locked door behind it. Find The Key And Unlock The Second Door From the locked door, turn around and run to the very end of the path. Jump across the gap and make your way to the checkpoint marker. This will flash a purple skull when you get close, causing three more of those geometric enemies to spawn. Kill this wave of enemies and then head right across the gap. Take a left and be careful when you get close to the checkpoint marker, as it will spawn spikes from the ground when you're close. Once the spikes have fully retracted, run up the wall, jump across the gap, and head left. Jump onto the platform and climb up the cubes to the right. Cross the gap, approach the edge, and use Gravity Anomaly to move across the walls until you are upside down. Turn 180 degrees and look for one more platform with the glass box that has the second key in it. Grab the key and bring it to the second door. Unlock it to, once again, discover another locked door. Find The Key And Unlock The Third Door From the third door, turn around again and this time jump down onto the platform to the left. Similar to before, launch yourself over the gap and follow the path until you reach a chest. When you get close, it will vanish and appear on the next platform ahead of you. Follow it until the chest reappears on the wall to your left. Jump across the gap and switch planes so you're running on the wall. Keep following the chest along the walls until you can finally interact with it. Doing so will summon more enemies, so focus on defeating them and then head to the back right corner of this platform to find the path once more. This will lead you to the final key inside a glass box, along with four chests you can open to get some upgrade materials. Bring the key to the final door to unlock the boss room. How To Beat The Physicist The Physicist is the boss this time, and it is a pretty dangerous one that can easily kill you if you're not careful. When the fight starts, you'll want to quickly run away from the boss, as it will chase you around the room and release a large AoE (area-of-effect) explosion attack when it gets close. It will repeat this attack multiple times before going into the air. Once it's high above you, The Physicist will launch three waves of four projectiles at you. Keep sprinting around the arena in a large circle, and you will be able to easily outrun these. When The Physicist comes back down, it will perform a sweep attack around its base, so jump up into the air and start attacking it to remain off the ground. This will let you get in a couple of combo strings before The Physicist begins pulsating again for the AoE explosion. When it starts the AoE attacks again, wait until it explodes, then dash in and hit it around three times before getting some distance from The Physicist. So long as you don't commit to a long attack chain, you will be able to get in to hurt the boss and get out before it can retaliate. Keep attacking the boss between its explosions until it flies into the air and starts destroying the arena you're standing on. It will then retreat, so follow the newly opened path until you reach another circular arena where the boss is waiting. When you land, it will split into four smaller versions of itself that you'll need to defeat. Just like the orbs you fought when hunting down the keys, try to take them one at a time, as they can deal a decent amount of damage and stunlock you if you get hit multiple times in a row. After they've been destroyed, the Physicist will reform. It will have the same attacks as the previous phase, along with two new moves. The first involves it flying away and launching several waves of spikes across the ground. Dodge either to the left or right to avoid them, while trying to close the gap so you can get some free attacks in when it's done. The Physicist's second attack sees it perform another pulse, but instead of an explosion, it launches spikes from the ground at your position. This is another move you can easily deal some damage to the boss during its attack, so long as you don't get greedy. Hit it a few times, and when you see the boss get ready to pulse, dash to the side to avoid the spikes. At around 50 percent health, the boss will run away one more time, so follow it to the next platform. Here's where things get a bit tricky, as The Physicist will summon two more orb enemies while remaining on the battlefield. You'll need to both deal with the boss and its minions at the same time. While you may be tempted to just attack The Physicist, focus on killing the orb minions first. These will be more annoying in the long run, so focus on attacking them between The Physicist's moves. Your damage window will be short, and you should always prioritize defense during this phase. With the minions dead, resume attacking The Physicist as you normally would. It has no new moves during this last part, so focus on attacking during the AoE explosion, sweep, and spike attacks when it's most vulnerable. Upon defeating the boss, you will gain access to the Astral Rebuke or Spike Combat Abilities.