Very sturdy for active play. I rescued 5 feral kittens and their Mom and set this cat tower up in the sunroom for them. Assembly was easy with all parts well marked. I did turn the bottom floating shelf forward to save a little space. The kittens were romping, climbing, leaping, scratching within 30 minutes of setup. I do have the tower secured to the wall for when all 5 kittens are on and in it. My cats think this is PURRfect.