Very well constructed and sturdy. I wouldnt recommend an adult use the slide but I tested everything else before letting my little one play on it and as a 63 250lbs male Ill tell you the thing is sturdy enough for me. I highly recommend you install the grounds stakes as instructed as it makes it even more stable and secure. 

One note I will make is that it took a total of 18 hours to assemble. 6 by myself and another 12 with 5 rotating helpers. It is a project of massive proportions so be prepared. When it tells you to drill a pilot hole DO IT. While cedar is strong and durable it WILL split if there isnt a hole where you put a screw. That being said if you VERY CAREFULLY follow the instructions 90 of your work will be pre drilled for you. However that is difficult and you will run into an instance or 2 where you put the board on the wrong way and itll be easier to drill a new pilot hole than to remove and adjust the board positioning. Just my 2 cents.