I have 5 children ranging from 18 years old to 21 months old and they all LOVE it. My three younger ones like to to do a "traffic jam" inside and then they all tumble out the bottom together, it's pretty cute to see! 
The directions were clear but the piece numbers are printed on the inside of the lip that gets put together so you can't see them once you assemble it. My husband and I found it much easier to assemble the first section and putting it up, then assembling the second section and adding it and so on.