This is a nice small one-bedroom apartment. It has everything you might need to live in even for long term. There is AC, heating, big TV, confortable couch, full-size bed, 2 pillows each, great WI-FI, fully equipped kitchen.
The only things you need to be aware of are that the above apartment has it's bathroom right above your bedroom and it seems that the ceiling is not very soundproof so you might hear bathroom-noise. Also the natural light is a little restricted due to being an interior apartment, and sometimes the neighbor's food and cigarette smells might enter inside. These are the only things you need to be aware of and they are small inconveniences, not deal breakers.
The location is ideal right in the heart of Malasaña. You have bars, shops, gyms and restaurants right as you get out of the building. Moreover the host Marina is great and friendly and will make your stay a pleasant one, the same as she did for you. Thank you!