Very easy to assemble! My three-year old had a blast helping me. We have a larger cat and he had some difficulty jumping from the second and third levels, so I moved the ball-toy to the second level instead of the circle platform and now he can jump around much easier. He's pretty aggressive with it and uses it multiple times throughout the day for napping and playing. Even with all his claws, the materials are holding up great. My husband will likely add a weight to the bottom platform because our cat gets pretty wild on this thing and we don't want it to fall accidentally on our toddler (we're those people who secure everything to the wall!).