There were several problems with the room we got.
In the bathroom, there was water coming down from the ceiling so the floor was super wet.
It was also super cold and we had to have the air-conditioning on for several hours to get it to a decent temperature (not ideal if you arrive late). There are also no proper duvet covers, so felt a bit unhygienic.
The windows do not open, and there is a restaurant right outside with tables right next to the windows with full insight into the room (there are blinders luckily). The location is great for exploring Athens, but there are many restaurants/pubs nearby, so good luck sleeping.
On a positive note, the host was nice and helpful and got us a discount for the trouble.