Rune Locations (Image/Text)

Here's the first rune, easily visible as soon as you exit the indoor area you spawn in.
Get over that protuberance and remember that landmark, you'll be going there.
Reach A - you'll now be seeing the second image. Go into the jump pad and there'll be a door in front of you when you land, go through it.
From the top of the landmark, go down and enter that door. From there just follow the path on the second image.

Go to the entrance, from which you can see the rune, then follow the path to reach it.
Get to A, then follow the path in the second panel.
At the end of this path you'll see the rune to your left.

Before you can get this one you first need to get the Yellow and Blue skulls.
Hop down and look to the left. You'll see the first following image:
Follow this path and the rune will be right to your left.
After going through the Blue Door, fighting the enemies in that area, and going through the now-unlocked giant door, the rune will be right ahead.

As soon as you exit the airlock, go to the right and hop onto a crate. You can see the rune from here.
We see this one at the start of the level but only get to it near the end.
Just play until you finish the fighting area that has the electrified water-flooded room.
After exiting it, turn to the left and it'll be there.

After talking to Samuel Hayden, go down the elevator, exit the airlock and activate the terminal.
The door to the rune will be open.
After acquiring the BFG and activating the terminal, the rune will be on the right.

After grabbing the Weapon Mod Drone upgrade, follow the corridor until you see a red door to your left. Look down and press E (interact button) - the rune will be on the other side.
After shutting down the portal and going through one of the two corridors behind the terminal you interacted with, follow this path.

That was the last one. You got them all.
Rejoice!