Seriously dummy-proof...I constructed it in 2 hours, alone, and that was taking my time. Honestly, I tried to make it more difficult than it was as I've had to construct some pretty badly made furniture in the past.
It's small but builds-high and there's a perch for all 3 of my cats. I chose to flip the top of it so that I could open the pen from the other side. That does mean the roof tilts towards your home if you're placing it at a window or door.
This was a good experience - I wish everything that needs to be constructed were this easy!