Great eye candy and convincing physics.
The story is very interesting, as you follow the steps of a seemingly ordinary guy put into an extraordinary position, in an island full of great visuals everywhere (up to the detail of the textures of the tree leafs and stuff). The fact that you can use a variety of realistic weapons and vehicles (including the famous hang glider) only adds up to the experience.
On the downside, the enemy AI is far from being excellent (for an example of an excellent AI, check the Half Life or Quake series), and I just don't get the developer's issue with the "save anywhere" nowadays. Come on, it's my problem if I want to save every 5 seconds (which I don't, mind you, but that's not the issue here), and if console players can't do it because of their console restrictions, then do a special game saving mechanism for them, and leave us, PC gamers with our own system!
These two (especially the second) issues drop the rating a bit on this otherwise excellent game.