It says a video devlog is permitted but in the “not permitted” sections it includes video devlogs alongside broken links.

Can I ask clarification for what is and isn’t valid?

 Video devlogs unrelated to your submitted entry are not permitted. You can use the video devlog format, but if it's totally unrelated, it will be disqualified. 

"This includes any link that doesn't outline the improvements to your entry."

such as social media feeds, video devlog, dynamic webpages, and/or any broken links.

I'll try to reword it so it is much clearer.