Thanks for taking the time to look at my guide! I will update it with information as I learn it (or as you all may feel free to add in the comments if you'd like). I created this guide as the layout of Tower Unite has changed over time (Cheers!) and there is no guide to locate the Hidden Dev HQ accurately as to date (8/11/19). It has access to vending machines and also some free privacy, if you know where to look. I often hear people in world chat asking for it's location so here is my description on how to obtain the achievement by locating it as easily as possible. Enjoy!

Note: A jetpack is required to complete this achievement. One may be located at Rob's Imports (one of the many shops located at the base of the Tower) for the price of 2,000 units.

We all spawn into the Plaza, via the subway. This is where our quest starts.

Proceed from your spawn point (the subway) up the escalator/stairs.

If you look "up" towards the ceiling of the Tower lobby, you will notice many "light holders". For this achievement we are looking for the dark blue lined light. It can be found towards the upper right of your view once you transcend the subway escalator/stairs.

Using the jetpack, hover up to the blue lighted light holder and land ontop of it. You will see a vent in front of you, walk up to it and you will find the option to select "E" for "???", Do so.

Upon entering the vent you should be prompted with your winnings and Steam/Collection Book achievement. Congratulations! Feel free to invite friends, enjoy the peace of secrecy, and/or use the vending machines or whatever it is you do!

Thanks again for viewing this guide, if it was of any use please show your thanks by rating it. I look forward to hearing your opinions/knowledge/info and if you ever catch me in game feel free to say "Hi!". I wish you all the best, thank you and GAME ON! XD