Most of the reviews for this product were positive but I always start by reading the negative reviews. I noticed a few stating the hammock was missing. A few complained about instructions without pictures. But the overwhelming majority said this was a great product so I chose this for our two cats. 

First, the hammock was included, as I would expect it to be. Instructions are clear and concise and DO include pictures. It is a very easy build process that took me 15-20 minutes. Everything is pretty self-explanatory once you get going. 

The tower is stable as I have an 8lb adult cat who jumps up to the house part and jumps down from the top platform. It never shakes or wobbles. 

If I had to give any criticism it would be the puff-balls on the elastic cord that are included. My cat had the cotton stuffing out of the first one in mere minutes. The instructions DO indicate you should get better, more durable ones. If that is the case, please don't include them then.