I mentioned Deus Ex: Invisible War in my last post. Invisible War is an interesting game. A lot of reviews panned it as being worse than the first Deus Ex, but I thought it was actually a superior game.
The thing is that where the first Deus Ex made choices obvious--usually through RPG elements like skills--Invisible War stripped out all extraneous choices, and built them into the gameplay itself. You could handle almost every situation multiple ways. But you never really saw all the different possibilities, because your first plan, your chosen playstyle, would usually work, and you never had to consider playing the game differently. If you approach every problem from the stealth perspective, you see the stealth solution first, and don't even consider the "guns blazing" option.
From a game design point-of-view this is very clean work, to build multiple solutions for every problem with such elegance. But the player ends up only seeing one facet of the game. RPG elements make the different paths obvious. If I can assign points to certain skills, I am chosing to *not* assign points to other skills. If the player never even thinks of using a rocket launcher, does the rocket launcher exist?
I suspect that Deus Ex: Invisible War would have gotten a lot higher ratings if two different reviewers had sat down and compared their experiences, and realized that they may have approached the game in two completely different styles and yet each style worked perfectly and seamlessly.
The lesson that Deus Ex: Invisible War taught me is that if you want people to appreciate their choice, you have to make obvious the fact that that there was a choice. People need to not only see what they are choosing, but also what they giving up.