All a Myst style game is a series of 2D, panoramic images tied together. The thing that ties them together are video transitions from one location to the other(in advanced games), and a screen fade in/fade out in less advanced ones. Each of those 2D images is a node, and each node can be accessed via a hotspot on the screen with your onscreen mouse cursor. When you click the node, you are taken from the current node to the next one via that transition.

Of course, you'll need to have your levels modeled out as normal and figure out where you want your nodes to be at in the level and do a prerender from there. I'm not sure how to pull off the panoramic effect when doing this, though. This is the cheat that makes a full, 2D image look like a 3D one and allows you to use the mouse to look in all directions from where you're standing. I'm guessing there are plugins or features for 3d modeling apps that will allow this style of rendering of an image, but I don't know for sure.