It seems that previous reviews of this hotel were fake altogether. When I searched for this hotel online, I did a filter for only hotels containing air conditioning. This hotel arose in the search, so I booked it. It does not have air conditioning. The receptionist even laughed and admitted that there is often confusion about whether or not they have it at the hotel. Yet, the hotel has made no effort to clarity this important issue (it was 90 degrees in Berlin both days I was there).
On to other issues, the condition of the hotel is very very old, without any updates/renovations whatsoever since it's post-WWII construction. My room literally had cobwebs in certain places, which demonstrates that housekeeping doesn't truly cleaning anything. I even noticed some cobwebs in their restaurant!
All furniture is old, worn and dingy. My room had a mildew smell. The shower did not work properly. The toilet made a loud horn-like sound when it flushed. The bed was uncomfortable. The wireless internet worked maybe 25% of the time. And none of these issues weren't even the worst problem I encountered.
The elevator broke the 1st day I was there so all of the older guests or guests with disabilities encountered an impossible time navigating up the hotels very steep stairs. Of course, as luck would have it, I was on the top floor as well, so hauling our luggage down those steep stairs was quite harrowing.
There was no fan for the sweltering nights either.