Lots of people struggle with quaternions and dual-quaternions initially - most of the time, it's the fear of the unknown. Sometimes, it's because the subject is called 'quaternions' which seems to send images of unsolvable complex mathematical problems to the mind.
They should give things friendlier names, instead of quaternions - the name 'snuggles'. No one is going to be afraid of snuggles! In fact, it makes you want to hunt it down and work out what is a snuggle!
It's a good demo to get those juices flowing as well and brush some basic principles - see if you can remember - like writing a vector and quaternion function without having to goto Google for help.