The IO Interactive twitter participated in Blocktober and posted images of early development builds of Berlin and Dubai.
You can also see the pictures from Dubai in the Dubai Location topic. You will see that the penthouse originally had a very different design.
Berlin petrol Station
Was this location inspired by a real life place? Berlin is such a cool location!
The Berlin location has taken inspiration from mainly Berghain, but also Kraftwerk. You can find many images of the inside of Berghain and Kraftwerk where youâll see the inspiration for Club Hölle.
There are similarities between Club Hölle and Berghain. One big similarity being that Club Hölle in Berlin is located in a former power plant, which is also where Berghain is located.
And something I just found out which I totally missed, it was mentioned here BERLIN, Germany (Mission #3) - Location Discussion - #511 by Hanga
The bouncer in Club Hölle is clearly based on Sven Marquardt, a bouncer in Berghain.
Comparison made by a user on Reddit
We have many Germans here who can chime in and give some more info on the inspiration for Club Hölle.
Thatâs awesome! Sounds like the place to be in Berlin.
I was just replaying Berlin and the shortcut that allows you to walk right into the club bugged me again. I was thinking this should have been a window shortcut. It would function the same way but then the club wouldnât have this unguarded door right near the entrance for everyone to sneak through. If it was a window at least you could understand why itâs unguarded. Maybe even after the player opens the shortcut from the inside the window still has glass in place that must be broken on every playthrough to allow 47 to climb through it?
This still isnât perfect bc why would a window be in that spot??? Itâs a little more believable though.
Way back when I was in college I worked in the theater building sets. The theater building was usually kept locked up except for one door in the back of the building, which faced an alley where trucks usually loaded or unloaded. That one door was broken such that you couldnât actually shut it so it was never locked and for whatever reason the school never bothered to fix it.
I look at the door in Berlin like that. Itâs a door that would otherwise be shut and locked except itâs broken and for whatever reason the club just doesnât bother to fix it.
I spare myself the irritation by simply not playing Berlin 
Seriously though, I agree with you. Itâd be better if it was a window or just a plain locked door.
The Berlin shortcut is the bane of not just the mission but the whole of Hitman 3 for me. Especially since after patrolling it becomes apparent just how many ways there are to get into the club without walking through the open door.
If it could just be a regular locked door, thatâs fine.
Another would be having a guard near or around the door, not constantly staring obviously, but just on a little patrol in or around the area would make it seem like it wasnât just a hole in the side of a wall.
Thereâs a shortcut in Chonquing (sp?) that Iâd feel was equally egregious. Itâs a corridor that leads to the rear entrance of the secret lab. Why isnât it that bad? Thereâs a guard you have to navigate past. Can you just knock him out? Yes.
But it doesnât matter, it adds something.
coming back to this level nearly a year later, I still wonder. this staging was intentional right? the guyâs haircut and suit look like the Constantâs:
Iâll admit, it got me the first time and I was about to be annoyed at such a cop out. all this build up just for Olivia to kill him?? 
still glad it wasnât the case haha
That wouldâve been awful. And off screen, no less!
But I think they just reused his character model
I think that guy is modelled after the agent from the announcement trailer. You know, the one who dies last in the forest.
I was gonna kinda say the same thing. I feel like itâs a reference â or some lingering cut concept â to the forest chase in the Hitman 3 reveal trailer.
I swear the old guy in the trailer was the Constant himself, but I guess that wouldnât really make sense? 
oh! yeah that would make more sense
gmtk made a video on berlin today
Always interesting. And this one includes some footage from a prototype or WIP version of the level and insight from the level designers.
And released on my birthday, what a gift!
heres a hypothetical: do you think having a working version of the manhole exit would impact your enjoyment of this map at all? probably not by much. tho i would love to breeze thru nko runs lol
Not really, although it was useful for me as a place to hide a Harveyâs body on my first playthrough. That was all I used it for anyway.
As they pointed out in the patchnotes, thereâs two other exits nearby (Bike, and on first run, the forest).
It just seemed a bitâŠweird having it.
I think during the first month we had the exit I was surprised at the placement. Because I dont really expect a sewer system to be where they put it on that map. It wasnât a bad idea to have more exits, it was just poorly executed because it shouldâve been put in an area that was more useful. Thought exercise for anyone else could be to guess where another place they couldâve put it is, but Berlin is the last place I would request for more exits i just wanted to ask a question
