This score reflects the pinnacle of Zimmer's electronic mastery. The electronics are incredibly perfect unlike anything you have ever heard before. If you hear this on really good quality speakers or Bose/AKG/Sennheiser headphones you will find yourself loosing into the sound itself. I found it to be that powerful.
I know that the main theme is not played every once in a while, but this score is not about the main theme alone. It is about the entire electronically charged sonic soundscape effect to be absorbed into.
I am not into video games but sounds like this can even fit into action packed video games.
I never found anything wrong with the electronic effects given to this score. It is absolutely timeless. Even current Zimmer scores though they are melodious, but none of them have this level of pure quality in electronics. The closest I can think of is Angels and Demons and The Da Vinci Code scores.
Although, I am emphasizing the greatness of this soundtrack, I would like to say that this score may not be your type. It may require you to have patience to get absorbed into the sound. If you are curious about this score and are willing to try out.. beware.
My suggestion is to forget the need to hear the main theme when you are playing this soundtrack from track 1 to 5. In this way, you can loose yourself into the soundscape.
In an unusual sense, this is a great soundtrack for meditation.