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 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.
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.
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.
سەرچاوەی فەرمی بە زمانی ئینگلیزی: https://www.thegamer.com/control-resonant-the-underpass-resonant-the-physicist-astral-key-locations-walkthrough-guide/
