If you are a fan of adventure games, you owe it to yourself to play Riven. While Myst broke a lot of ground in the adventure genre, Riven blows its predecessor on every front. The scenery is still photo-real, even after almost 13 years. The puzzles in Riven are seamlessly incorporated into the environment. Where as Myst's puzzles felt more like a Rubik's cube you stumbled across, Riven's puzzles truly feel real, as if you were actually on this strange set of islands.
The environment pushes the excellent story, as you continually feel motivated and even if you don't know exactly where to go, you know what your mission is.
As a Myst-obsessed gamer, I've played every Myst game dozens of times.
Riven continues to be my undefeated favourite. I cannot recommend this game highly enough!