A great game that spawned a great sequel and... some other ones.
The added scenes in the Director's Cut are welcome, and flesh out the story a little, but the new sections at the beginning of the game where you play as Nico feel a little padded with unnecessary puzzles to extend the playtime. Ironically, a few things that were in the original game are missing here, like some pieces of dialogue and an option that used to result in a death and game over. Nothing very significant is gone though, much more has been added than has been lost, and some things were cut for good reason, so it's not a problem unless you're a purist. The Director's Cut has the same graphics, resolution and sound quality as the original, but newly recorded lines are of higher quality; which actually makes the rest of the sound much more jarring, as the old lines of dialogue are very low quality in comparison.
For those who aren't familiar with the game at all... Well, two things make a good adventure game: story and puzzles. On the story side, it's a globe-trotting kind of adventure about finding ancient clues, exploring ruins and mausoleums, uncovering murder plots, and a little bit of magic and mysticism. Although it sounds quite serious, it's actually a pretty vibrant and light-hearted game with some good humour and exaggerated characters. Overall it's pretty grounded though, and rarely laugh-out-loud funny. The story makes me think of a mix between Indiana Jones and The Da Vinci Code. On the puzzle side, it doesn't indulge too much in the typical "adventure game logic", puzzles usually make sense (with a few exceptions), and you don't have to roleplay MacGyver that much (again, with a few exceptions). So overall, great. Not every puzzle is entertaining though, and some are a little obtuse or long-winded.
I almost forgot to mention the music. I love the music in this game! Very atmospheric soundtrack, kind of minimalistic but soothing, and always fits well with the scene.