I just discoverd this part is also available on gog. I played the DVD version of this (which has higher resolution graphics than the version offered here, correct me if I'm wrong gog). Some things look graphically impressive considering the age of the game. Overall, the game has it's good moments but it lacks something. I got the impression the first half is better and closer to the "magic" of part 1+2. The ending is really sudden! But apart from graphics, it's not as good as the first two parts be it story, music, atmosphere, puzzles. Why they didn't take the route like an "Eno prequel" or something closer to part 2 is beyond me. I have yet to play part 4+5.
This game is a classic. There are not many games that come close in terms of atmosphere to this game (and part 2). It also has stunning music (for example the sunrider theme), clever puzzles and graphics which are still somewhat pretty for todays standards. Point-and-click adventure magic for me :-) It is right up there with the Myst series (but in a different way).