This here is the complete walkthrough for Half-Life: Alyx Chapter 9: Revelations in which we will show you how to complete the mission and mention any achievements you can earn here.
Half-Life: Alyx Chapter 9 Revelations
The mission starts with you making your way up the ladder but right in front of you is an alien! So you should shoot him down. Now go to the place where you just killed the alien for which you will have to climb up a ladder again.
Now Alyx will talk to Russell about what is happening to the station right in front of you upon which you will be directed towards the station. Kill the headcrabs crawling towards you.
Follow Russell’s instructions and follow the path in front of you! As you pass the two dustbins you will find a broken room with a staircase, go up! On the way, you will find health so use it too!
As you move further you will confront another Combine Soldier so kill him. Now go down and past the broken bathroom to open the door which will take you to the next room.
Follow the path and pick up supplies on the shelves. From here pull the wooden flanks restricting the way to the next section. As soon as you enter the area you will see someone being pulled up by a rope!
From here go right. Now go further and turn left, kill the two aliens and then interact with the lever on the right wall to bring the lift down.
Hop inside it and it will take you up. Move towards the right using the big pipe and then jump on the left. You will find two hostiles here kill them.
Head up the ladder and clear the area off of the enemies. Find your way to the upper levels of the building and go left to walk down the stairs.
From here you can also upgrade your weapons using the resins you collected. Once you are done doing that head up the stairs on your left and open the door to access the open world.
Kill the aliens on your way as you advance further along the rail track! When you find the broken train engine move right, where you will find a room!
Go past this room and go right till you find a door with a big red logo on top of it. Interact with the lock system and open the door.
You have to connect the blue lines with the corresponding locks which you will figure out how to do! The door will open when all the locks turn blue. When the door opens and you go inside the mission ends, earning you the High Water March achievement in Half-Life: Alyx.