We bought tickets on-line as well as the "Zoo it All" pass and the "Glow Package".

Zoo it All - This came with unlimited train-rides, carousel rides, and 4-dimension playing of polar express in their 4D theatre. We only ended up doing the 4D theatre, because the line was so long for the train! I loved the 4D movie, it lasted 15 minutes. It says it would be $4 for the showing, and the zoo it all pass was $9, so would not get the zoo it all if we were to go again.

Glow Package - This came with glasses that make the lights look like snowflakes, a Denver zoo hot cocoa plastic cup with lid, and one glass of hot cocoa! The refill stations are not truly "refills", as they cost $3.77. I think the glow package was $8, so it seemed worth it to me! The glasses are cool and hot cocoa was delicious.

Zoo Lights - The lights are very cool and animal themed themselves. Many of the animals were out, even at 6-8pm. We say elephants, giraffes, zebras, hyenas, hippos, cranes, flamingos and leopards either outside in their exhibit or inside. If outside, you have to have a good eye to see some of them, especially if they aren't moving. They also had the reptile/fish/snake exhibit open, which had lots of animals.

It is very crowded, but not crowded to the point where you can't move or see what you want. You can easily walk around people if you don't have a stroller, wagon or wheelchair. It is a little harder to get around with the strollers, but they seemed very popular for families with kids.

There are several places with food, drink, and rest areas to take breaks. We stayed for 3 hours and only left because it was fairly cold. We enjoyed every minute, other than waiting in line for the 4D movie for 10 minutes!

Parking seemed a bit stressful, we Ubered and they just swing in and pick you up in the loop. I would recommend Uber if you have a party of 2 or 3. I think you had to pay to park too.