After a quick stroll on Myst Island it seems to be working fine here.
W7 64bit
Windows XP SP3 compatibility mode and 'Run as admin' applied to shortcut.
@1920 x1200
Full AA
Direct 3D ONLY (No T&L as that seemed to have caused some funky colors issue and lag)
I also have the setup.exe (the configuration tool) set to run as admin.

Give me a minute, I'll get it and try. I love Myst, so no skin off my back!
UPDATE: Hoo boy. It's running pretty shoddily. It stutters like hell, leaves artifacts that stay for a bit in the game, and it crashed when I opened that door on the docks.

That did not work for me.

Are you running the config tool as admin ?
I just played a bit more.
Went into the dock forechamber, flipped the library entrance a few times, flipped a few marker's switches, read Catherine's note...
Everything is working and looking great.
I have a GTX 295, 195.62 drivers.

I set it with the same settings I set the shortcut to the game:
Windows XP (Service Pack 3)
Disable Visual Themes
Run this program as an administrator
I have a GeForce 9800 GT, and the latest NVIDIA drivers.

The config tool only needs the 'Run as Admin', and that's just to make sure it really saves whatever configuration changes you make.
I don't know why it's glitched at your end. It was for me the first time it booted, but changing the Direct 3D settings to just Direct 3D with no T&L solved the issue for me.

Oh, NOW I SEE WHAT YOU WERE SAYING WITH T&L! Sorry, misunderstood what you meant by that before. Thanks!

So, it's working ?

Yep!

Awesome ;)

realMyst wasn't a big seller from what I recall, so I guess that's why they opted not to remake any other titles from the series.
But personally, I'm really fine with Myst as it was originally released. It's all about the ability to immerse yourself in the game, in spite of the limited technology. I will never throw out my copy of the original Myst (which I still own on CD-rom, the non-Masterpiece Edition original release) to make room for a remake, no matter how well-done. Don't get me wrong, I will buy realMyst from GOG because I do like it, but for me it doesn't surpass the original in terms of sheer quality. It's basically the same game, except it's a little prettier and it has an arguably superior control scheme. Maybe I'm just nostalgic about the original, but I could never get hooked on realMyst in quite the same way. To some, Myst felt like clicking through a slideshow of pretty pictures. To me, it was a world. A place I don't mind revisiting every once in a while, no matter how archaic the technology might be.

Are you saying you see the whole screen at 1920x1280? Not just a little viewport in the middle? Whoa.

1920 x 1200 in my case, but yeah. Looks great.

So has it been confirmed that it works on Vista? I can't get my old version to work right.
Defiantly buying it if it does.

GOG's Advertisement says Windows XP and Vista 32 and 64. I have not been able to get my disk version to run in vista.

So original that you need a Macintosh capable of running HyperCard stacks to play it, by any chance?
Back on track, though-I'm tempted. Very tempted. I played a deluxe edition or some other re-release of Myst for Windows, complete with a built-in hint system and all a while back, but no longer have it. (One of the things I lost in the move from Virginia to Georgia a decade ago, along with System Shock 2, Magic Carpet 2, and some other things.) However, I never got a chance to try realMYST, and this looks like as good a chance as any.