Not very compatible with Windows 8.1. I was hoping that the availability on Steam meant this awesome game would be miraculously ported to modern platforms, but I had the following problems:
- no animations worked. Anything that was animated just didn't happen, such as the message from Atrus giving you the clue to rotate the tower.
- occasional full crashes. You can't even use Task Manager to kill the process, you have to reset the machine to recover. The crashes were mostly due to saving the game, but also occasionally due to animation.
I got it to work through the whole Channelwood Age (+- about 5 reboots), but because of the above I had a hard stop at the clock tower, whose puzzle involves animation and continually triggered a freeze.
I'm off to try realMyst-Masterpiece, which was developed much later (2014) than this (2000).
UPDATE: "realMyst: Masterpiece" is definitely the way to go. Even ported to a 3D engine, the game still looks visually appealing, but more important is that it is rock solid on Win 8.1, and they cleaned up a few gameplay issues.
If you're interested in playing Riven, I can highly recommend the one from GOG.com over the one on Steam. I tried both, and the GOG version was also rock-solid compared to the Steam version.