The rating is for the experience rather than the actual apartment.
Short version - ok if... you know to provide your own bed linen, don't need internet, don't mind a constantly wet bathroom, and two of your group are VERY close friends.
Long version - The apartment itself was generally ok as far as this kind of property go, fairly well equipped and in a decent location. However there were several problems.
The listing photos at time of booking showed 2 sets of bunk beds, which was what we needed for 4 individual adults. On arival we found one set of bunks in a small alcove had been replaced by a raised double with ladder access from the foot end only, which was entirely unsuitable for our purposes. Photos need to show the property as it is now, not as it used to be (listing photos are now up to date).
There was no bed linen provided (not mentioned on the listing - when booking I specifically asked if bath towels were provided and the lack of bed linen was not mentioned in the reply) and listing did not offer an option for rental of ben linen. On contacting the owner after arrival they just said to use one of the linen rental companies in the resort. This was impossible as they were all closed when we arrived, even if we had known this was something we needed to do.
The listing says there is internet. There is not. On contacting the owner they said to use the free tourist office wifi, but that couldn't be accessed from the apartment. I needed internet for work so this was a major issue.
There is no shower curtain which means that once one person has showered the whole bathroon is awash. It seems to have been planned as a "wet room" but there is no drain in the floor so the water has nowhere to go!
The listing mentions a pool, sauna and hot tub. They don't appear to exist within the building.
On a safety issue, the hidden lights under the kitchen cupboards get extremely hot and because the switch is next to one of the bulbs one of us badly burned their finger reaching under to turn them off.
(Vrbo aren't interested in handling customer complains, they just say to post a review with the issues)