A couple of days ago, Cyan's Eric Anderson posted some delightful links via Twitter:
Here's a fun treat for all the Myst/D'ni/Uru fans out there... The original pre-Uru, pre-Mudpie "DIRT/Descent" demo, in all its fully-playable glory! Don't ask us for support, just cross your fingers and hope it works. PS: This thing is 19 YEARS OLD! tinyurl.com/DIRT-Descent pic.twitter.com/hxzYqKLD2F
And for all you HARD CORE fans: Here is the 20-year-old Pre-DIRT "Nexus" Demo built before Cyan even acquired Headspin! It's so old you need to install a (included) Glide GPU wrapper! Also, I have no idea how to solve the "puzzle". Enjoy! tinyurl.com/NexusDemo99 pic.twitter.com/DtoR0PEpBt
Extra Double Bonus!!!!!! Here is the playable "Hector Cove" demo as well (also from around 2000)... Because why not - right? Go harass some janky birbs! tinyurl.com/HectorCove pic.twitter.com/o2yYaMEF5I
(Headspin was an independent studio which developed the first version of the Plasma 3D engine. Cyan acquired Headspin in 1998 and used their engine for RealMyst, Myst 5, and all the versions of Uru / Myst Online. A GPL version is now available.)
I never played these demos; I didn't start tunnelling into Myst Online fandom until 2003-ish. And I'm sorry to admit that I still haven't played them. My Windows gaming machine is currently packed in a box, and it'll be a couple of weeks before I have access to it again.
But you're not me, so have at it.