Hacker News Reader

TWM (87) and FVWM (93) are still maintained today.

Don't forget CDE (93) and XFWM (96), still getting releases.

Xfwm has been rewritten from scratch at least 2 times. I can't imagine there is any code left from the original releases. Plus it used to be a CDE clone and that was dropped around version 2 when it became a light Gnome clone.

Window Maker was also first released in 1997.

Cool aliens? Is this a reference to the Alien 5/Alien 17 theme?

I don't remember what it was called, but yeah, something along these lines. It really looked cool.