I'm a bit disappointed in the challenges page. The copy on the site tries to emphasize how difficult they are and that anyone who passes the challenges would be considered a serious candidate. While they were fun challenges, they're way too easy.
I completed multiple challenges then sent along my information. As soon as they saw a resume that didn't include much experience in the security domain, I was basically ignored.
Recommendations for Praetorian:
If you want the challenges to mean anything, make them more significant so that completion would actually be a strong positive signal for the candidate rather than a BS-detector. If someone passes your challenges, you should be begging them to work for you, not the other way around.
Cut back a bit on the elitist rhetoric, it is a bit of a turn-off. I think it will attract more mediocrity and scare away some great talent.
Final word: the challenges are fun for anyone and if you like that kind of thing, you will enjoy beating them.