In chapter one, after the flooding section, climb up the ladder and enter the vent. After exiting it, look under the pipe and get in the sewer vent to find the Carson's Hideout.

To get this achievement you need to destroy all four radios in the game. Pretty much all radios are easy to find and play a loud music.

In chapter 2 you can easily find two radios.
-
At the end of the chapter you find another radio in room with two soldiers next to two soda machines.


The last radio is in chapter 3 and is probably the only radio that you could miss. In the North Entrance there is a vent entrance on the floor. Get inside to find the last radio in a corridor.

In the same room where you find the third radio there is one working soda machine, break it to get this achievement.

In chapter 2 go to the Infirmary where you can get a crossbow. In the same room you are gonna find a scientist on bed, hit him until you kill him to get the Flatline Fiasco achievement.

In chapter 2 you are gonna find some prision cells, in of them there is a scientist and a banana.

-
To get this achievement you need to shoot the "ELECTRONIC CELL DOOR CONTROL" to open the door and steal the banana. (Just walk over it and recover some health)

To get this achievement you just need to escape and appreciate the Nuclear Sunrise. 😎

Right after you find the weapon locker and the second radio in chapter 2, a soldier will open a door, get in and kill all the soldiers, then look up behind you. You are gonna see a vent.

-
On the right there is a box, push it close to the wall, so you can jump on the electric boxes and reach the vent.
-
Inside the vent go to the left, you are gonna be in a elevator shaft, use the ladder on the left to climb down and get in another vent on the floor below.
-
Now you can finally get in the Systems Control Room:
-
Find the V.A.T.S Manual and open the website: http://ipcscorp.com/
Scroll down and click on the V.A.T.S. OPERATOR MANUAL[ipcscorp.com]
In the manual you are gonna find three test codes:


-
Enter and listen the three messages in the V.A.T.S. machine.

-
The machine is gonna like you, so have a good time with it. ( ͡° ͜ʖ ͡°)

After making some love with it, get back to the vent, the machine is gonna get angry, get back to the room and it's gonna destroy itself, unlocking the double secret achievement.

-
After unlocking all achievements it's gonna give you access to a bonus epilogue map. Enjoy.