Secret messages
Did you know that in Hannah and the Ice Caves, there is a secret message in the background on every level? – Sparkiness
The hidden programmer
In the last bonus level (Muahaha), you can sometimes see a blonde guy in the background, where a hidden message would be on the normal levels. He’s about three times Hannah’s size and impossible to miss (this usually happens if you have to restart the level). – spacecat7n