The apartment was great for the price. Good location, reasonably clean and spacious for a single person.
A few things I would improve would be:
The bed: just a single boxspring with only a top on it is a bit shabby. Could've gone for a smaller double (140 cm) with an extra mattress.
The shower: put up something like a shower curtain, current situation is quite messy with the toilet getting all wet when taking a shower.
The kitchen: a bit more plates, cuttlery and pans.
Communication: because of the hesitancy to provide information about entrance codes etc before checkin time .. I didn't really feel welcome and trusted. Came across as a bit awkward and suspicious.
Overall I did enjoy my stay in Oslo, partly because of the apartment which in the end felt quite cosy and private.