On a slow connection, it’s supposed to passively download the site for offline viewing and update the contents as the connection is re-established. However, in my experience, it’s hit or miss. When my connection is acting up, sometimes it downloads the content but not the styles or images while 75% of the time you get to play with T-Rex. Highly recommended, by the way. He’s a blast!
https://en.wikipedia.org/wiki/Dinosaur_Game has a lot of information 🙂