Hard to read about Boundless features when tabs at the bottom of articles on the homepage do not work. Tried on Firefox Desktop, Mobile and Brave Desktop, none of them successful.
The entire website is horrid. It’s not even responsive (gracefully adjusting across viewport widths). I offered many times to build a website for James free of charge and never got a response :(.
I believe the issue is with this:
playboundless.com appears to always be using the latest version of jquery but the .live() function was removed a while ago so this JS error is preventing subsequent JS from working which is, in turn, breaking the buttons you’re talking about as their event handlers aren’t being called.
You can view the website here functioning @Aslanex : (webarchive version)
There the tabs at the bottom of articles on the homepage do work.
Not a final solution but at least a workaround so you can see more information.
Another thing of note is that the website images and video all contain content from Early Access. All the stuff and planets from EA were wiped and new planets were generated.