The building is a huge square about 4 stories high and the center is completely open as if the core was removed. In the center is a gigantic jungle gym, reaching almost 4 stories high. This is great for big kids, tot's won't manage it and little kids will have a hard time neither should be in it alone because they can exit the structure at any level and you will be hard pressed to keep up if you're not in it with them. There are also many platform levels where they'd pass children and/or adults alone. Jungle gym (IMO) is for 11 and up (to be safe).
The outer zones are suited for tot's and young children 7 and under. There is a great water table and sand table, circle time (in the library of sorts) is scheduled and excellent. However, it's unstaffed at other times and children should not be in there alone. There is a secluded nursing cubby room in there as well for moms. Try to hook up with scheduled events.
I found that the center works for big kids only and the outer area for small kids only. I found the staff to be unenthusiastic and not easy to find outside of enclosed rooms. There is a locker area and picnic area where you can purchase vending machine drinks and snacks but you can't buy lunch inside so bring it with you if the kids will be hungry.