Interesting visuals, but horrible gameplay
The two major plus factors of the game are it's graphics and it's music. The game consists of static, partially animated prerendered background images. While the quality of the images doesn't reach genre highlights like Myst, they still look at least interesting. They also greatly help the overall atmosphere, which gets supported by the mystic and unintrusive background music.
The Linux port is solid and the game can be started even without a previous installation.
Unfortunately good graphics doesn't make a good game. While it's the concept of the story that different ages and cultures of the world are mixed in one dimension, this definitely feels strange. Example: when leaving the loge of an opera you enter some strange blue and open-ended place with crystals spread everywhere. These abrupt changes of locations let the game look like the designers rendered some random scenes and placed them randomly in the game. Moreover it makes the navigation in the labyrinth difficult, as no contextual relation exists between the scenes. This will often result in confusion ("Was the Western scene or the future space ship behind that office door?"), though a good map system is integrated in the game.
Moreover a lot of the scenes don't serve any purpose, as no interaction is possible and you just run through them to get to the next place. While this definitely helps the feel of loneliness, it also makes the game feel very lifeless.
The worst part of the game are the riddles. While several of them are relatively logical, some of them are definitely not, and the results of an action are usually unforeseeable. What makes them the ultimate fun killer is the fact, that "wrong" actions like pushing a button at the wrong time can make the game unsolvable, as these actions can't be undone. As the game doesn't give clear hints that the action was wrong, you can continue playing for hours not even noticing you have an useless savegame (yes, this happened to me several times!). And as the game doesn't give any hints, you have to completely find that out yourself. Happy guessing!
The Bottom Line
The concept of the game doesn't seem to be completely mature. More often than not I felt the artists rendered impressive 3D scenes and decided to make a game out of it later. Dozens of dead-ends and frustrating puzzles completely ruined the game for me. After having to restart the game several times I found myself printing out a walkthrough and following it step-by-step.
The music of the game is excellent, but the game engine doesn't seem to be able to play music and sound effects at the same time; when something happens, the music is muted until the sound effect has finished.
Just one last comment on the interface: The game uses a strange menu system where the bottom bar can have two different modes which can be changed by right-clicking it. While the bar looks ugly and the icons are not always unambiguous, it works surprisingly fast once one gets used to it. And it's the first game I've seen where the inventory consist only of fullscreen views of the items :-)
All in all, I can't recommend this game; as Dave Schenet already mentioned, it's more of an (meanwhile outdated) 3D render demo than an actual game.