Before you go, make sure to go online to the zoo's website and get the free, timed entry passes required for admission. It's probably best to get them a few days before your visit.
We loved the playful orangutans and elephants! Their interactions - elephant with elephant, orangutan mama with her baby - were cute and funny. We were a bit disappointed that we never got tickets to see the pandas. They're free but a limited quantity is released hourly to regulate capacity. You scan a QR code at any of several Panda Kiosks throughout the zoo, then go to the link to check availability, and if you're lucky, get your passes. If not, keep refreshing the link. I consistently tried for approximately 3-5 minutes before and after the times they were supposed to be released (30 minutes past each hour) for 3 hours. In one attempt, I "got" one, but it kept disappearing upon confirmation. I finally gave up and enjoyed the rest of the zoo residents. Maybe if you get there upon opening, you'll have better luck than we did..