Here's my single Axel as of 2005:
The additional 1/2 revolution sounds more innocent that it really is! Not just that, the forward take-off can be tricky. Skaters often take longer to learn the single Axel than most other single jumps, some even claiming double jumps before "getting" the Axel. In an earlier post, I had put together a series of videos of my "Axel Progression"!
Various other interesting facts about the Axel jump are captured in Wikipedia!