Since a few days, the final Making of Catyph is released on the Black Cube site. You can read it here:
Don't forget also that you can read the Post Mortem of ASA too:
By the way, the development of Catyph will be paused for a few days starting today. I take part to the Myst Jam hosted on Itch.io (9-18th January). I will try to create a little something in less than 10 days. News, screenshots and WIP should be posted here from time to time, or on The Icehouse site.