Well, apart from really dirt dishes, a dirty bathroom, broken chairs and beds there wasn't much wrong with the apartment.
Granted, it was more or less cheap for the location, yet I still can't emphasize enough how dirty the whole apartment was. It was like the cleaning personell just changed the bed covers and left again.
The check in process was unnecessarily complicated since you first had to go to the KeyBarcelona office to check in and get the key (although the personell was really nice).
The furniture was in a really bad state: One bed squeaked heavily, so much so that you'd wake up from it in your sleep, the frame of another bed was broken and at least the third bed was intact.