What a world to explore
The story is absolutely marvelous (and epic, of course), and will keep the player going, trying to figure out the meaning of all the mysterious events that are taking place. The setting is very imaginative and yet tangible: dual worlds, one of technology (a futuristic Earth) and one of magic. Both are very well fleshed out and colorfully depicted, and each world has a definite personality to it that is so wonderful to feel as you're exploring. The characters are well crafted as well, especially the protagonist, April Ryan, who is gradually revealed to be one of the most complex and realistic characters to be found in a videogame. I came to genuinely care for her and her stakes in the whole drama. Dialogue in this game may seem long to some, but it is very well written, and the voice acting is perfect. The gameplay doesn't disappoint, either: puzzles are interesting and well incorporated into the plot.
Overall, I would say that The Longest Journey is the best adventure game to come along in recent years (by that I mean the 21st century; in the adventure genre, four years IS considered recent! the genre is fading, so sad!), and easily one of the best of all time as well. Definitely give it a go.