First, the facts. The place has very low ceilings so if you're taller than 1.75m you'll be constantly banging your head against doors and light bulbs, and ducking to move around. The apartment has no ventilation except for a main window so without a way to ventilate it properly it's perpetually stinky. Also there is no closet or drawers so you'll be pulling your clothes from your bag during your entire stay. The kitchen is ill-equipped, missing basic stuff like normal-size dishes, cutting knives, etc, so be prepared to eat out during your entire stay (granted, not a bad option given how amazing food is in Lisbon in general).
It really breaks my heart to leave a bad review but I cannot recommend staying at this place except maybe for a very short stay.