Is it me or is this code seem unnecessarily complicated?

This is a queue I have used myself:
https://github.com/Demolishun/...

This is a queue I ran across:
https://github.com/cameron314/...

I understand the second link shows a queue that does a LOT more than the first example. It supports multiple produce/consumers for instance. It is also lock free. However, it seems really complicated to me. I was always under the impression that the more code you write the harder it is to maintain.